Doubles are doubles, if you haven't seen the 'Rock boobs video' you may want to look for it(if it hasn't been completely scrubbed), it very much shows someone that looks like the Rock but that isn't built like the Rock and if memory serves there was also a noticeable absence of some tattoos...

Technology that is known and publicly acknowledged is rarely the actual level of technology available and in existence(NSA had square miles of server farms in the late 70's...), plastic surgery and medical procedures is just a form of technology, what they can actually do with it certainly is quite a bit beyond what is show on shows like Botched and what not....

Reportedly the first human clones were created in the late30's/early 40's and Bush Jr. looking like a straight clone of Bush Sr. certainly suggest that this is indeed true...