Unless you were assembling your inner WS's with OEM parts only and "fresh made" rubber stripes..., these would never again fit (and seal) like the first day! Especially not after an old, rusty frame has been restored...
Even on the original WS-assys they usually end up collecting rainwater in the lower frame portion and keep the moisture inside, doing its business...
So far I have restored X-many of these inner WS and never felt the need for those stripes; even less trying to find a source for new replacements.
Without anything else the glass should- and normally does- fit a bit loose inside the frame assembly; so just use some tape to hold it evenly spaced; then get a gun & tube of PU-based sealant; make a nice, continuous bead - all around 4 sides, both faces; let it cure; next day carefully cut off excess material; eventually touch-up lacquer scratches, or spray-paint the whole part after masking the glass...
End-result: as good as new, or better!
Stay away from anything silicon-based as sealant, there! (It will be VERY difficult to ever paint those frames again, at the least...!)
G.