Wing glass
 

Can the driver side wing glass be tighten up without removing it from the door on a post coupe 1964

Yes.

Remove the door panel and then feel up under the wing window and you should find a nut on a stud below the middle of the glass. There should be some washers and a spring above the nut. The spring provides the friction. Tighten the nut up on the stud to provide more spring tension and that should firm up the wing window movement.

HOWEVER, these studs and nuts are typically pretty corroded and the nut may be hard to turn so be careful trying to turn it so you don't break off the stud. A shot of penetrating oil might not be a bad idea.

If the window is really loose, that stud may already be broken off or the spring perhaps has broken.

There is also a stationary washer right above the nut with a lock tang that secures the nut. This has to be bent out to turn the nut.