First time I've noticed those wire holders Tim. Looks like another one of those little projects that's gonna keep me from working on the trucks.
I've been working most of this year with silicone and casting resins to come up with gaskets for the '54-'55 radios speakers. Also knobs that fit like the original ones, support brackets, driver side pads for converting the passenger radios to truck, the speaker supports, special nuts and spacers, ammeter fuse holders. This week I'm making the molds for the rubber bumpers for the Fresh Air defroster doors and the tool box keyhole plugs under the seat of the '54 and a few other non important little details.
So if I get a chance I just might draw up those two original style plug wire holders and see if it's practicle to cast them in semi-ridged urethane. Looks like the front one is for 2 wires and the rear one holds 3 wires.
DG