Normally, any part they add a letter to means that they have made a slight change to it. That is why you see some parts that end with a, b, c, or d.....they are the same part with just a slight change.
The first five numbers in the part number is the part itself. The numbers after the hyphen is the year it first came out. For example, a 45733-48 is a tube plug oil seal used on the front forks of the FL series bikes from 1948 to present. If this part had a letter following the -48, then it would still be the same part but with an upgrade of some kind. (i.e.; 45733-48A).
Nuts, bolts, washers (common hardware) and most o-rings do not fall into this part number system. They typically have up to five numbers only (i.e.; part number 11105 is a rubber o-ring where as part number 0207 is a washer).
that's all good but for some reason the dealers parts book says the A revision fits 04 and up but we compared it to my 02 and can't find anything different. for all i know it could be the shade of the brass in the inserts or the shade of the black paint. guess i should have asked if there's any difference between an 02 and 04 inner faring 'cause me and three other people looked at it and can't find anything different.
Not sure if this makes a difference but, I think 04 was when they went to a different angle on the fairing. I don't know that it would make a diff on the inner because I thought the new angle was achieved with a new mount bracket.
I don't know if it helps any, but I just replaced my original 2000 inner fairing with one taken off of a new '06. The inner fairing was replaced with a painted one and the original innerfairing fit my 2000 just fine. They should fit your '02 OK as well - even though they are not listed that was in the material.