Is your bike 1st or 2nd Generation 955i Body style?
If your 2001 is first gen body style, '97 - '01 t595, t509, 955i will all share same body bits, Speedy or Daytona.
The second generation of 955i started mid 2001, so some 2001 are the diff body style.
my riders seat sits tight against the tank and both bolts easy to insert,pilly perch hooks in with no gap between
them and clicks in on rear catch,only time i've had a problem was it all got over tight when fuel tank expanded !
maybe rear catch has moved ?