Well, after having done some searching around and reading
THIS, it kinda looks like I'm not going to get a Bose system AND working 5-band EQ at the same time, as they are actually mutually exclusive options. Searches of CDM part numbers cross-referenced to the heads they came paired with seem to confirm this - and another interesting tidbit is the apparent lack of BALANCE control on the earlier to 93 Bose CDMs. Didn't see that one coming... lol.
So I think, unless I just happen across one, my prioritized search of the yards for a Bose CDM is over - since I must have the awesome-looking 5-band EQ cassette deck in my truck and functional, and the Bose system doesn't support it
.... And I'm going to have a secondary aftermarket deck in there anyway, soooo..........yeah lol
I have a Bose head unit I've had since 2011 out of a 1999 Blazer to pair with this Bose amp I just pulled, and what do you know... All of that works great. It's almost tempting to throw all that into my truck for now until I can swap dashes lol.