Solid and Liquid don't look 100% like BB, pretty easy to see that in MGS4, only Solidus is the exact clone. Solidus also would have looked a lot older than Solid so it's easy to see him not noticing anything past, "huh, I guess he kinda looks like an older me, maybe".
As for him not noticing the president's resemblance to BB, he probably did but just dismissed it as coincidence.
BB looks older, had a beard and mustache and was missing an eye. Solidus would have looked a little younger, not been as a battle worn, would be clean shaven and still had both eyes, not to mention their competely different demeanors