Glenn, Fixing the seal on the vent windows really should be done by completely rebuilding. Replacing the seal around the frame requires complete disassembly. But sealing around the glass with gasket maker or windshield sealant should work. The glass seal is a tape stuff Link but requires removing the glass from the frame.
Here's a couple excellent how-to videos.
www.youtube.com/watch?v=z6o2KEETyxY&t=144s
www.youtube.com/watch?v=1xEZFaa_ivY&t=128s

You should have no trouble installing the latch and pin with the vent window in place.

Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.