Not sure what your seal looks like .
My vintage DS with no bedroom slide , I used " canopy tape " from auto parts store . It's used to seal truck canopies to the top of the bed rail .
3/16" thick 2" wide , self adhesive on one side and plastic on the other.
Other shaped seals can be seen at this site ; below.
If you don't see what you need . please post a picture of what yours look like.
www.pellandent.com