I've been contemplating how to make a replica back for this set. I do have an original metal back from an older 16R12 model that looks like this. Note the AC power plug doesn't lineup. I figured I'd cut one out of masonite, drill some vent holes and cut a hole for the CRT to stick out.
Just before I got started today, unexpectedly the set's owner shows up with a pickup truck full of vintage TVs he was moving from his cousin's place. Between the sets I noticed some lose backs including the one for this set
I'm so glad I hadn't started drilling any holes yet

I wonder why they switch form metal to masonite ? Maybe to save money ? Maybe because of the relocated AC power plug ?
If anyone would like a pattern, I'd be happy to trace it out. Looks pretty easy to replicate.
Here's a closeup of the Roto-Scope antenna instructions.