[Ron Ramirez]

Hi David, and welcome!

Also, congratulations on your find.

The cabinet like yours, with the more pronounced "peak" to the top, usually holds a Code 125, 4-band 16 chassis. Having seen a photo of your set elsewhere, and seeing the hole for the tuning knob shaft and that it is a small hole, this proves your set is 100% original. Obviously, when Philco switched from the flatter top to the more pointed top of this style cabinet, they still had a few leftover 16-121 chassis, so they drilled a small hole for a single tuning shaft in the cabinet. Models that use the 4-band chassis have a large hole so the concentric tuning knobs will fit.

Anyway, to answer your questions...

1. The tuning knob should be a large hex knob, with a set screw so that the two-speed tuning of the 16-121 chassis can be accomplished easily. The band switch knob should also be a large hex knob. The volume and tone knobs are small hex knobs.

2. I do not know the answer to this one, sorry.

3. Not that I am aware of at present.

4 & 5. I suggest you purchase the Philco 16 Code 121 schematic package from Chuck, so that you have all of the factory production changes as well as a nice, large 11" x 17" schematic and all available factory data.
http://www.philcorepairbench.com/schematics.htm