The only reason for Oswald to be guessing would be to somehow establish an alibi for the time of the shooting. But what would be the purpose for him to somehow concoct an alibi for where he was some 5 minutes prior to the shooting?
Why try and make up an alibi by guessing about something that happened approx 5 minutes prior to the shooting and to just name some people he "guessed" could have been there? None of it makes any sense. Even more so, because it would be utterly stupid to tell this story, if it never happened in the first place, and he had no reasonable expectation of Norman and/or Jarman confirming it.
This whole "he could have guessed it" BS goes nowhere. It has been dreamed up by LNs who can not give a plausible explanation for Norman and Jarman being were Oswald said they were at the time he said they were.
It was possible to see the area of the shipping department behind the elevators through the door opening of the Domino room. Anybody who has seen a diagram of the first floor should know this. In fact, you could see all the way to the other side of the building, where the stairs were. As we know that Norman and Jarman did in fact leave their position on Elm Street, prior to the motorcade's arrivale, and walked on Houston to the back of the building, in order to enter it and take the elevator to the 5th floor, a far more credible explanation for Oswald's statement is that he was indeed in the Domino room at around 12:25, when he saw both men enter the building and walking towards the elevators. He saw them but they just didn't see him. What was written in the various reports were not Oswald's words verbatim, but distorted recollections from people who. most likely, had no first hand knowledge of the lay out of the building.
And Chapman, if you are going to use a photo, at least try to use one from the Domino room and not the 2nd floor lunchroom!