Hi
A couple of points about choosing a Roland synth for your retro-gaming PC (I have owned both the internal card and external module).
The ISA card version you are looking for is called Roland LAPC-1. It is a very long ISA card, on my old 486 machine it touched both ends of the PC chassis, so it may not fit on all ISA slots on your PC.
However, I later sold it and bought a second-hand external Roland CM-32L module for two reasons (CM-32L is 100% compatible with LAPC-1 and MT-32):
a) Many PC games "screwed up" the sounds of the Roland synth. Or more precisely, some games didn't initialize it properly when you run them. This meant that many games would sound completely wrong with LAPC-1 if you had played some other game just before it.
The only way to cure that was to switch off and switch on the PC between different games, because only that would properly intialize LAPC-1. Simply rebooting the PC would not help.
However, with external modules like MT-32 and CM-32L, you can simply switch off and on the module, and it is initialized properly for another game. No need to do anything to the PC, just run another game.
b) Having an external Roland module allowed me to make The Ultimate Retro-Gaming PC sound-wise: Roland SCC-1 (Sound Canvas) for General MIDI/GS games, and external Roland CM-32L connected to SCC-1 for the MT-32 games. This setup worked perfectly, whereas with two "similar" sound cards in the system (Roland SCC-1 and LAPC-1) could possibly pose some problems, or at least using them would not always be so straightforward because they want to use the same I/O address, IRQ etc.
At best, my retro-gaming PC had Soundblaster 16 (for FM synthesis and sampled sounds), Roland SCC-1 (and Roland CM-32L connected to it), and Gravis Ultrasound. I am surprised I got this setup work perfectly. 😁 However, I sold GUS as there weren't that many games supporting it natively, besides vanilla General MIDI+sampled sounds, which I already got from Roland SCC-1 + SB16 combination.
Of course, you also need some kind of mixer for your sound cards, if you want to hear Roland music and sampled sounds in games at the same time.
Hope this helps with your decision. Depending how well MT-32 emulation progresses, I might be willing to sell my SCC-1 and CM-32L at some point. But not yet. 😁 Got to love them, I just love the MT-32 and Sound Canvas music in many old PC games...