'94 Roadmasters (and Caprice/Impalas too I think) have different radios and different wiring. I tried finding a '92-'94 Buick CD Player out of a Park Ave or LeSabre and all the units I could find were expensive and of questionable quality.
I was thinking about swapping in a '95-99 CD player, but I ended up picking up a used Pioneer so cheap that there was no point.
To make this work, you would have to build your own adapter harness, and you'd have to open up the dash cover a bit too, but that's more time consuming than anything else. Make sure the radio you use is a Buick unit so it has the proper dimming signal interface.