Chuck,
You'd stated that you had a Muncie?
Did someone replace your tranny at one time?
As Walt mentioned above, the 65 4 speed was a one year only deal and was a T-10.
The easiest way to check is to look on the bottom of the tranny housing and if it's the original deal, you should see what will look like the letters "GS" cast into the case.
As a Muncie, you'll probably have better luck locating a shield than you will locating on for the 65 GS T-10.
Chris