Mismatched groups do not bug me much on old race bikes, --- it just means they were used, stuff broke, and was replaced or upgraded with no thoughts to future collectibility.
if it leads to a good deal for us as buyers, so much the better. If that bike was a 53 , i'd pay that much for the frameset alone if i had a chance -- so great score
As an aside, it almost makes me sad sometimes to see an old bike that looks like it was only ridden 500 miles then put away. Anybody buying a Pinarello, Colnago, DeRosa, Paramount etc etc likely had already been through a cheaper bike or 2 before going big, so it makes me wondder what happened to make them abandon the dream