As someone who has seen 70 years plus of audio development now, I have to say you have some misconceptions.
First there were no discrete digital formats until 1997 except magnetic tape. Before that, all the surround coded formats were analog formats. That includes Dolby pro Logic.
The earliest attempts to market "Quadraphonic Sound" to the public started in the seventies and was slow to catch on. The first to catch on was the Columbia SQ system and its derivatives. This was also slow to catch on, but started to have a vogue in the late 80s and during the 90s. as manufacturers introduced Quadraphonic decoders, with four power amps and an SQ decoder of some type. Below is an example.
For individuals like myself who disliked receivers, there were outboard decoders, that went between the preamp and the four power amps. I had a high end Electrovoice decoder, that could handle SQ and its variants. It is boxed up somewhere in my collection of obsolete equipment.
These systems were not over impressive, and front to back isolation was far from perfect. But I do still have some quadraphonic LPs from that era.
In addition there were four track discreet four channel tapes, and four channel reel to reel recorders to play them back. I never got into that as Studer Revox wisely avoided it. I never owned a Japanese reel to reel machine and have always regarded them significantly inferior to their European counter parts.
So before discovering this thread, it so happened that last night I played a Colombia SQ LP of antiphonal Brass via the Dolby DD Sur upmixer in my Marantz 7705 AVP.
The results were actually better then I remembered from the old matrix decoders.
Now the speaker arrangement was not as now. There was no center channel and the four speakers were in the four corners of the room.
The LP I played was of antiphonal Italian brass music, with a total of four brass choirs, one in each corner. The front left to right separation and localization was excellent. The front to rear localization was fair, the rear left right discrimination was pretty much absent. Most of the rear power went to the surrounds, but a significant amount to the rear backs. So that meant that the sound was emanating essentially from the corners.
The firm Pentatone have released an number of these Quadraphonic masters on SACD. I have some of those, an obviously the four channels are kept discreet.
So I suspect those games used the SQ matrix or a variant of it. So, I would recommend that you play all this Matrix early surround recordings, including Dolby Pro Logic using the Dolby DD Sur. upmixer. I think that will do the best rendering for you.
In my researches I found that these Quadraphonic recordings, were made with modifications of the Decca tree mic arrangement. I find this interesting as that is having a renewed interest for Atmos recordings.
