I've been told that if you're there in person and have said jacket in hand, if you have a letter saying why you need a replacement, you should be good. I don't have first-hand info, but the letter and a NATOPs jacket should be all you need. Yeah, I know...if only the world worked that way.
FWIW, when I was the MO at my last squadron, my MCO was trying to get our Skipper a replacement jacket. When he talked to the people at NPA, they said the letter was what was needed. I don't remember if it was resolved before we (my Skipper and I) left.