It sounds like you have a unique problem which will take a bit of trial and error to figure out. If you have the old vent assemblies you can put them back in. If not you can try to find some used ones and rebuild them. Once that is done you can buy reproduction regulators that are correct for that year and then add the glass. That would get you back to square. Note the regulators for the vent assembly doors are different than the one piece door glass regulators. Look in the parts catalogs to identify which one you have or will need to change to.

If you want to retain the one-piece glass you may have to kluge some things together. The previous owner may have modified the door internals to accomodate the one-piece glass and the old style regulator. If that is true it may complicate the installation of the vent assemblies or will require you do the same mods to the left side door. This will include repositioning the front glass channel bar further to the front inside the door and using the old style regulator. I have not done this but others may have and hopefully they will chime in.

Providing some pictures may help or do a search for "one piece glass" and see if you find anything that will help. Good luck.