I changed out my vent windows and one of the regulators last fall. I purchased complete new assemblies from Classic Parts of America at $225.00 per side, chrome. A little pricey but they went right in and I was moving on to the next problem. There is a bolt welded to the inside of the door that the bottom of the vent assembly attaches to. Is this still there? I don't know if a single piece of glass would work with this bolt still mounted inside the door. The regulators are available at several places. I have purchased from LMC, classic parts of America and American Classic truck parts with good experiences with all.
As to wether or not you should do it, I have been trying to do our truck as close to original as my budget and skill level allow. Martin

I'm waiting for some warmer weather before I start sitting on concrete and working with metal again. Gloves just don't seem to work for me and I don't have the luxury of a garage or hanger. Just jealous of those that do.