1963 R50 vs. R60

A friend of mine bought a 1963 R50 last night but the motor isn't original, the motor is an R60. I realize the difference in displacement but my question was are there differences in the frame size or other features between the 2 bikes?

I've run a '53 R51/3, '57 R69, '62 R-60, '59 R50, '76 R75/6 and '82 R-100 over the decades since 1964. The differences in power not that great for the pre 750 twins.. a detectable change in acceleration from the R50 to R69, with the R60 around midway between. R50 a bit sluggish with 2-up and gear. something like 26 vs 30 HP difference. The 750 to 1000cc series are much faster (and stop better). Kinda like wood vs fiberglass sailboats... each has it's aesthetic and feeling qualities, but the performance of the front forks and brakes, brisk acceleration, superior cornering of the R-100 dwarf the earles-fork trucks. IMHO!
They bolt up same, I believe head pipes same for R50-R60.