As earlier mentioned, I went to B&C Friday and picked up some new vent windows to replace the not so solid glue-in units. Here is a little photo run down of the work done.
Before, cardboard and masking tape. Always a classy look!

Here is one of the new units from B&C. They came out of an early '80s cabby, so needed some modifications.

I had to grind the rivets holding the vent frames to the uprights since my original upright was shorter and missing the lower mounting tab. You can see there is also an extra top mounting tab for the cabby door frame which I don't need and it would be in the way.

Here is the new frame assembly riveted together (my short upright and the bolt-on vent frame) ready to install

And now we have a properly functioning vent window that will not fall off on both sides!

All in all, not a bad job and I am so glad that I won't have to worry about them now. I was fortunate that my rubber seals were in good shape. Dave J