Yes, if it is a universal design. For the most part, chevy, buick, pontiac, and olds had there own transmission bolt pattern, but in the 80's GM was putting chevy engine in everything. They designed a 200 metric OD trans. that has various GM bolt patterns.
Are you sure your regal has a pontiac engine? Where is the distributor mounted? pontiac and buick are on the front of the engine and chevy and olds are at the rear.
Hope this helps. Christopher