Yes.
The Dootch Motor Co. (Harris Brothers) lot faced Jefferson. The back of the lot was up against the alley. So yes, Callaway was at the front (closer to Jefferson) and Guinyard was at the back (the alley).
Guinyard, standing on the sidewalk, would easily see Oswald throw down shell casings. Maybe your problem is that you're unaware of where two of the shell casings were found.
Like I said, learn the case.
Barbara Davis and Virginia Davis each found a shell casing. Both shells were located on the side of the house they lived in; the side facing Patton, not Tenth. Guinyard, standing on the sidewalk on Patton, sees Oswald throw down a couple shell casings once he (Oswald) turned the corner from Tenth onto Patton.

Oh, please...Get out of your own way.
I'm talking about this "
...rolling them with his hand.." SG would not be able to see from that distance.
Mr. GUINYARD. He came through there
running and knocking empty shells out of his pistol and he had it up just like this with his hand.
Mr. BALL. With which hand?
Mr. GUINYARD. With his right hand; just kicking them out.
Mr. BALL. He had it up?
Mr. GUINYARD. Yes; he had it up just like this.
Mr. BALL. How was he kicking them out?
Mr. GUINYARD. He was rolling them with his hand--with his thumb.
Mr. BALL. Rolling them with his thumb?
Mr. GUINYARD. Checking them--he had the pistol up just like this [indicating].
Mr. BALL. Did he use his left hand any?
Mr. GUINYARD. No; I never did see him use his left hand.
Mr. BALL. He didn't?
Mr. GUINYARD. No, sir.
Once again, you make some other argument and have it out with yourself.