My 88 Regal had 14inch alloys from the factory, and the steel wheels I used to run my winter tires on were 14 inch as well...which I believe were originally from an 88 ish Lesabre. Still have those winter tires and wheels kicking around, and had them on the GS last winter for storage while the alloys were out being refinished. They fit without issue.
I just automatically assumed they would fit any 88-93 1st gen with factory brakes. Brake Rotors on RockAuto start showing some different fitments for 94+ cars...with some showing they fit 88-96 models, and others showing that they only fit 94-96. Not sure if that's incorrect....or if so some of models/trims started getting the larger 1.5 gen setup up front at some point.
So 14 inch wheels on 1st gens is something I was definitely aware of!