Moparguy

First you'll need the proper gasket for installing the SS Trim. Steele Rubber sells both gasket/seals for the front windshield. One for using SS Trim (deluxe) and one without the trim.
https://www.steelerubber.com/search...odel=3600-truck&style=2-door-flatbed

I assumed you were referring to your '51 3600?

If you do however have the correct gasket installed to use the SS Trim I believe it would be almost impossible to install the trim while on the truck. Everything I have researched says
to install the trim on a flat work surface prior to installing on the truck.

Good luck and keep us posted!

Jeff