Yes, boomer's tale could just be an implant. So could anybody's tale, even Dualla's for that matter. But,and I'll do some checking, cause my memory is fuzzed, Boomer told her story to a non-cylon and they seemed to know what she was talking about as if it was a great tragedy. Still could be an implant, I'm just postulating...it could also be something more.
Somehow humanoid cylons had to be introduced into the population. Why not start them out as refugees after an "accident"...and have them worm they way into their roles? It just seems a reasonable theory to me.