When ordering and after having received some parts for the rear cowling, I have identified the following issues in the online parts catalogue:

The main issue is that the online catalogue seems to combine the parts listings of the 1994 PDF catalogue with the pictures of the 1996 catalogue. At least this is true for the fiches that I checked. This means that the numbering in the pictures is not consistent if Honda decided to get rid of parts, gave them different numbers or didn't make them available individually any longer.
I checked this against a 1994 catalogue PDF.

H-14 Rear Cowling

The difference between the 1994 PDF and the 1996 on-line catalogue is:
The two self-adhesive rubbers in the grove of the cowling's rear end had #11 in the 1994 catalogue but these weren't any longer available as individual parts in 1996. The list below the fiche erroneously doesn't take that into account because it is the 1994 list. So, to order any part for the 1996 model after #10, add 1 to its number to get the correct list entry, e.g. if you want to order one of the springs #21 which hold the two halves together, order part #22 from the list.
Screws #24 are special: Order part #20 from the list.

I13 Rear Mudguard

This time #7 from the 1994 PDF catalogue is no longer a separate part in 1996, so all part numbers starting with #7 need to be incremented by one to order the correct part for a 1996.
Apart from that, the Honda order part number for the battery cover (#5) is wrong for the R2T and R3T, it should be 80107-KV3-831 instead od 90107-KV3-831.

I had the idea to add more findings to this post when I order the next batch of parts, but this is not possible. For some reason this forum does not allow to edit posts after they have been submitted.