Which model of vintage Gretsch do you have?
Some older Gretsches developed the need to have their neck reset. When this happens, the neck sometimes gets loose at the joint to the body. The neck angle becomes too low, and that makes the action raise since the neck is pulled by the tension of the strings. Sometimes (for example on a 1969 Streamliner I have), the neck joint is stable, but the action is too high -- and, in my case, the extension block under the higher frets, next to the neck pickup, actually pushes up the high end ofthe fingerboard. On my guitar, I will remove the fingerboard and sand down the height of the extension block and make sure that it is perfectly flat with the neck itself, then glue the fingerboard back on.
The neck joints in 1960s Gretsch hollowbody electric guitars have 3 basic designs:
1) the dovetail inserts from the front of the guitar, and there is a black circular dowel on the back of the neck at the heel of the neck, which covers the screw which holds the neck onto the body
2) the dovetail inserts from the treble side of the neck, and the dowel is on that side of the neck. (This style was used on the thinner-bodied hollowbody guitars)
3) (actually is from the 1970s): the joint is similar to #2, but the truss rod is adjusted from the body end instead of up on the headstock.
Most of the resets seem to be required by guitars with the first type of neck joint.
I hope this helps!
Jim in Virginia