Maybe! Or maybe Mr Williams did spend a v. short time eating his lunch up there on his own, awaiting the expected arrival of his workmates, before being ordered off the floor by... someone.
Initially he tried to hide any visit to the sixth floor. Then he gave a series of garbled versions of the truth.
They never believed anything of the sort! And most likely it was Mr Williams himself who did the encouraging on the score of backing up his story.
I'm not arguing that it was Mr Piper, just that he fits Mr Rowland's description much better than Mr Williams does.
If not Mr Piper, then a member of the assassination team.

How very annoying this particular area of study is.
"Of course it's not Piper," I thought. But best to check it out.
Piper watches the parade through the first floor window. Except there aren't first floor windows. Its those thick, distorted glass blocks and a concrete 'lattice-work'. Piper did not watch the parade through these.
So what puts him on the first floor at the time of the assassination? Troy Eugene West is at his wrapping station, as he always is, facing the very 'windows' Piper says he is at:
Mr. BELIN - Did you see anyone else on the first floor while you were eating your lunch? Anyone else at all did you see on the first floor?
Mr. WEST - It wasn't anybody. I didn't see anybody around at that time.
The only other person to put him on the first floor is Dougherty and his fantasy BS about coming down after hearing a shot.
There's nothing that puts Piper on the first floor. His claims that the window vibrated because of the shots (shots West never heard) now seems really suspect. He also claims that he and Truly had a shouted exchange concerning the elevators. This seems suspect as well as Baker has zero recollection of it.
I can't see anything that prevents Piper being spotted in the snipers nest by Rowland.
It's so annoying
