As a rule of thumb, a higher resistance pickup goes well with a higher resistance pot. But the difference of say a 480k pot and a 500k pot are nuances - it's not a make or break thing. You will hear a bigger difference if you exchange a 450k pot with a 550k pot. Keep in mind that the tolerance of such pots is usually 20%, i.e. a 500k pot could be anywhere between 400k and 600k (usually lower than 500k though)! Some manufacturers specify closer tolerances but that will trigger an upcharge.
If your pot is working fine, i.e. no dead spots in the taper, no scratching I would keep it. If it has issues I would buy the BKP 550k in a heartbeat.
Cheers Stephan