Castings numbers , which you posted mostly aren't really good for identifying a trans other than platform specific pieces as all the maincases will have the same number .

But that said the one where I can somewhat see the tailhousing and it's a 69 down B body tail housing , is it a 23 spline or 18 spline input shaft ?

8 31 67 is the CASTING date , there are no plates screwed to the castings , what you see as screws are the identifiers screwed into the mold itself.

is there a flat machined pad on the right side of the trans ? Need to see what casting number is on the bearing retainer , the casting date points to a 68 model year trans.