Yamaha WR650 carb

I picked up an old Yamaha ride on very cheap as a non-runner. The reason was
that someone has assembled the fuel pump wrongly. Thing is, it's a WR650 and
the engine plate confirms this. According to the Clymer manual the carb
fitted is from a 90 ish 500 ski. This is the type where the fuel pump is
round and fixed by about 8 allen screws onto the carb. Anyone know if this
carb was ever fitted to 650s? If it's the wrong carb then it's obviously
going to run badly.
TIA, Pete.