Yes taper lock bushes/pulleys come in series, so for one size taper lock there may be 30 different bores you can get. As an example the pulleys I got for the Beaver spindle were both the same
P28-14M-40MM/HTD but I got two different bushes to suit, one for motor and the other for the spindle. Motor one was 2012-24 and Spindle 2012-50. 2012 is the series size and 24 or 50 is the bore size. You wont be going for anything that big so the series number will be different as well.
Hopefully BSL and AFC will just spec you for nearest but they may well try to match as with you giving them part numbers they are probably thinking its from a machine and you need exact replacements. My local BSL is open Saturday mornings so maybe yours will be as well and you could give them a call, if not it will have to be Monday
Hood