There is a company that just started selling all different seals for RVs. Try Steel Rubber Company. If you can send a profile/shape, size and picture, they could either match it or make it. The make all kinds of seals for the Old Car Market. You can also get their catalogue to compare. I don't work for them but have used their products.
2012 SunSeeker 3100SS Toad-1962 Futura Average 100 + days camping