I've been trying to rebuild my windows
and have removed a ton of silicone, replaced the cranks and a broken pane but was at a loss when it came to finding replacement gaskets that fit in the slots at the bottom of each window pane.
The local RV dealer recommended that I try a mobile home supply store nearby. I went there and told them about these old windows
I was working on and they said they had no window gaskets that would work. They only carried new stuff.
Then I showed them the old gaskets that I had removed and right away they had the solution. The gaskets that are used in the shower doors are similar to what I was looking for. I bought a 10 foot piece for less than ten dollars. A little work with an exacto knife and I'm back in business.
I hope this helps others that have the same problem.