I believe there are places that can remake a VIN sticker (such as if the trailer was in an accident and that sidewall had to be replaced), but I've never researched them. Chances are it would look a little different than original, but would contain the same info.
As John said, a lot of times the clear film over top is what fades. If you can scrape that off with a fingernail, you might reveal the original sticker info. It seems that most Sunline VIN stickers got a clear film, just some weren't very thick or good.
I think you could check with your local police department- ask for a VIN check and once they verify, ask them where they recommend you could get a new sticker from.
If you need the info for a VIN sticker, like tire specs, weights, and build date, let us know.
2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9473.8 (as of 6/18/21)
1997 T-2653 Blue Denim, #5471
1979 12 1/2' MC, Beige & Avocado, #4639
Past Sunlines: '97 T-2653 #5089, '94 T-2251, '86 T-1550, '94 T-2363, '98 T-270SR