A good question, whether they have other copies or not. Tigh has been shown to ask about his memories, in the revelation scene, he talks about the two wars, but not about the question of how he was born before Cylons were made. Indeed he should be asking, I presume they don’t want to push this question on the audience too hard, we don’t see all they say.

Or it could be conditioning, as you say. We remain entirely uninformed as to why the 5 are sleepers. I am guessing it is part of some plan the 5 have to bring them closer to their human side by regularly making copies who live as human.

It’s less clear, by the way, why Boomer was programmed as she was. The Cylons seem to be good enough actors. Gina, Caprica Six, D’Anna, Doral and the rest all lived among humans undetected, though Baltar sussed out Doral but he may have access to extra info. So it doesn’t make a lot of sense but may just have been a plot device.