Thanks for all the replies. Unfortunately the CHB-160 GTE Key System Manual links (all of them, unfortunately) just give you the index and nothing more. Searching for the sub-chapters on the other link wind up nowhere too.

If you look at the TCI website link to the 1970 AE Key System equipment and go to Page 2, mine was very similar to the 'Wall Mounted Unit' on that page, though I don't recognize the internal configuration. The dimensions given on Page 3 for it are exactly right. I probably had that AE apparatus cabinet, just configured more like my Northern Electric QUJ9A one:

https://pacwestbell.com/?page_id=99

As the dimensions are exactly the same. Covers probably *are* the same, as someone else suggested. I bought the QUJ9A thinking it was the 'right' one, but...I still think I'm after the AE 10A2 equivalent if I want to be anal enough to be *exactly* right...though they're functionally interchangeable.