Terne plate, that’s interesting, I’ve heard of it but this is my first time working with it. Steel sheet coated with lead and tin to make it easier to solder joints. I see it held up fairly well over most of the outside, but looks like not so well inside, I see rusty surfaces in there.
What a pity they didn’t make it out of brass.
Quite a few dents on the bottom, not at the support pad areas, can’t guess how they got there.
There are two 1/4" threaded studs on the front, in line with the internal walls. They do not line up with anything on the chassis such as tie straps or anything. My guess is they were for attaching to some kind of assembly fixture for holding the parts together while it was soldered.
Looking at this thing, I was reminded of the old joke that a camel is a horse that was designed by a committee. This tank is made of a single sheet wrapped around to form the top, bottom, front and rear, but there are about 25 separate other pieces. That notch on the right front, seems to be no purpose for it. The brake linkage is below it. Likewise the tapered notches at the front corners, the springs are at least 3" below them. Was all that left over from the '36-37 cars?