This is as close to a complete PROM ID CHART that I've ever seen. It's from a Tuner Cat Program and the information seems to be consistent with GMSPO information:
LT5 PROM INFO.png
There would be no reason to remove it to ID it. The scan ID that's in this chart should be what's displayed on a Tech1 or suitable scanner. Now if it were thought to be a modified PROM then ??