Well, seeing as one does not require a (R)PAL to own an antique, and no records of transaction are needed, one could just get a friend to obtain the letter...
Interesting comment. Interesting, because it begs the question of HOW can someone try to register an antique firearm with the CFC if that person only collects antiques and doesn't have an RPAL? Is there some sort of a double-standard we don't yet know about? (example: if you admit to having an RPAL, they'll automatically register your antique... if you say you don't, it's the old system where they actually have to do the legwork of verifying it for you prior to sending the letter).
I've met quite a few collectors like these who don't want to bother with the red tape of getting an RPAL, but still collect antique class firearms, which is fully legal of course. So, in essence,
if the OP did not have an RPAL, how could they forcefully send him a reg certificate for his pre-1898 .41 Colt and put the onus of proving actual status on him?
Also, how are you supposed to obtain letters prior to shipping antiques from the States? Are you supposed to register a legally antique firearm that's currently in someone's private collection down in Alabama and then go through the hellish task of sorting all the paperwork for importation, THEN have it deregistered once it's here? Can anyone say RED TAPE and BACKDOOR GUN CONTROL???
(Seems like some old time Lieberal-appointed bureaucrats at the CFC are in dire need of being shown the door by PM Harper, as their "best before" date expired in the late 1990's... along with the rest of the Lieberal reign)
Hint: Next time, tell the techs that you don't have an RPAL or that you're not going to disclose your license number. They used to ask your permission for that, but the argument was that it would simply speed up the process of obtaining your proper mailing address, etc. It had nothing to do with forcing reg certificates down your throat though.