Can someone identify this inspection cover?

I have two bellhousing inspection covers that are different sizes. The one on top in the picture has part number 2843892 on it and it fits my 1969 smallblock bellhousing. The bottom one in the pic is smaller in size as you can see by the measurements. It looks a little wider in the pic but it's not, it's just the angle I took the picture at. Anyway, I would like to identify what the bottom one is for so I can sell it. It has no part number stamped in it. If anyone can tell me what it is for I would appreciate it.

Looks like small block truck with np435, but you didn't give the depth

Maybe a three-speed cast iron BH pan?