I don't know if he did or not. I know that even if he did, that does nothing to exonerate Oswald. Oswald might have been scouting possible shooting locations for the best possible angle. He could have been contemplating taking a shot from the west end window after the limo turned on to Elm St. He had plenty of time to look over the situation before deciding what his best option was. I'd say he ended up making a very good choice.

I'm glad to see that not even you can quite swallow the WC line on this issue, which is really saying something.
To imagine that Rowland guessed there was a slender, white male with a scoped, high-powered rifle on the 6th floor of the TSBD building moments before the assassination is too much for even you to accept.

It is obviously the case Rowland saw this man, to suggest otherwise would have you replacing logic with the miraculous.
This made the WC's narrative even more difficult to construct - how is Oswald wandering around the 6th floor, "scouting possible shooting locations", without BRW noticing?
How is that possible?
And why is the man with the rifle wearing a shirt Oswald wasn't wearing that day, and didn't have in his possessions?
And why is there a black man in the SN?
And why isn't Bonnie Ray sat looking out of the closed third set of windows?

Rowland's testimony was utterly devastating for the false narrative the WC Sham was trying to create so, rather than simply accepting the testimony of this witness, they took the unprecedented step of launching an FBI investigation into a private citizen with the express purpose of finding anything they could on him in order to nullify his testimony.
Luckily for the Warren Commission, Rowland felt the need to lie about how intelligent he was and this was enough to dismiss his witness statements regarding the man with the rifle and, more to the point, the black man in SN window who stayed there until around 12:25pm (around the same time BRW went down to the 5th floor).
It was a truly devious and underhand strategy.

It’s a shame a stereoscopic camera wasn’t used here, that would solve everything.  I still say it’s Harvey and Lee discussing where to have a bite to eat later on.

It means that most Americans didn't fall for the lies, hoaxes, and decade long media propaganda to keep an establishment figure that they could control in the WH.  No other such person could have done it.  The establishment has a lock on power in this country using the system and money to stay in power.  They have run the national debt up to $40 trillion and counting with approximately half of Americans not paying any taxes.  That is not sustainable.  The only real change will come when that house of cards collapses.  None of that has anything to do with your paranoid fantasies regarding Russia.  Russia is a paper tiger mired in a stalemate in a war that they could have won in a single week had they the abilities that you attribute to them.   This is a self-inflicted situation.

Sez Herr Comrade Smith

Capital punishment cases are largely appealed through the federal court system and attorneys have learned how to delay executions not for years but for decades with appeal after appeal. Recent executions have been for murders committed 25 to 30 years ago. That is a ridiculous amount of time. By contrast, Perry Smith and Dick Hickock murdered four members of the Clutter family in November of 1959. They were captured and tried in 1960 and hanged in April of 1965. Five years seems like plenty of time for appeals to be filed and work their way through the appellate courts. Those sentenced to the death penalty should be given one bite of the apple in appealing their sentences. They should be required to file all of their objections to their conviction and sentencing in one appeal. After those appeals are denied, the only grounds for putting off their date with the executioner would be if they can present compelling evidence they were wrongly convicted.

Let's bring back the electric chair, the gas chamber, hangman's noose, or the firing squad. Let each state should choose the method of execution without concern for whether we kill these Barstewards humanely. They never gave their victims that consideration.

I am not arguing against Capitol Punishment
  I have no idea what you're muttering on about

The second official investigation into the JFKA, HSCA-1979, concluded otherwise, and found the LNT un-compelling, or implausible.

There were a lot of smart and skeptical guys on the HSCA, and they  were not "CIA did it" CT'ers, or head-in-the-sand LNT'ers.

They concluded likely LHO was not the only gunsel on 11.22.

I agree with their assessment.

The "LNT'" is that the evidence is overwhelming that Oswald was the assassin and the evidence is non-existent that he had any accomplices. Both of those are facts.