You can swap any /5 or later oil pan onto any /5 or later engine, you need two things:-
1/. The pan
2/. The correct length oil pickup (and bolts) and (depending on pan depth) the extension piece that extends the "depth' of the oil pickup
Buying a pan on spec without getting the oil pickup that goes with that pan leaves you with the annoying job of "whittling" an extension piece from a lump of alloy (The one I had to make for a friend's R100RS that he decided to mount a late model pan to I made using only a hacksaw, drill press and mill files - it took a day)
The first "interesting" part is deriving a way to measure how long the extension needs to be.
But if you get the oil pickup with the pan, no problems. Although I do not believe that this would ever be a problem with the R65 Ihave a nagging memory of having to donate my old and somewhat weary R100 centre stand to a friend who was fitting a big sump to an r50 or R60 as the cross piece on the the original stand was too high for the deeper sump - but it was a long, long time ago.