If the series were to co-exist in thesame universe, commander Adama would be over 600 years old then when he reached earth. I did not type an extra zero, in the original series when Adama seperates the battlestar from the fleet, colonel Ty warns him that the FTL system has not been used for decades, and the ship might break apart when using it, and in the episode where Starbuck and Apollo find a hidden communications room that receives a television broadcast of the moonlanding in the 60's, it is mentioned by Adama that the galactica is over 500 years old, and that there is noway of telling how old the original broadcast is, so they decide to leave it be, and not mention it to anyone.
In the re-imagined series, the battlestar Pegasus is more advanced, bigger, and has superior weapons, in the original series, where Cain was a man, and Apollo's girl was the Cains daughter, the ships were identical in every way.