x,
SU95's on test usually use 1F*** codes and don't have any prefix to the number part as you state. After delivery they change to a full RA- registration or the other country registration and also change their hex codes to that appropriate to their new registration. The new registration is not the original with the inclusion of RA-* and the pre-delivery serials/registrations are as you state re-used.
We have had 1F**** codes in the database for SU95's previously but as they were no longer applicable these were deleted when the frame was delivered and a new registration/hex taken up. There are some such codes in the d/b at this time, probably no longer appropriate but as I don't have a c/n available for them I cannot state for any certainty so they would probably be more appropriate as being noted as SU-95 test codes.
Any verified code is added to the d/b
Alan