86 flywheel vs 87 flywheel, both 3.8

I had my flywheel on my 86 engine break. I have an 87 engine just lying around. Both are vin 3, and both are from LeSabres. The flywheel on the 87 has a group of three holes drilled into it in different spots than the 86 does, approximately offset 10 degrees when put side by side. I'm trying to verify beyond the AZ part numbers that they are indeed the same. The holes I'm talking about are about 1/2" diameter, along the outer edge of the flywheel near one of the holes for the TCC bolt. Can supply pics if needed. I'm not sure if they are balanced in a particular way or not or if it even matters. In the meantime, I'll be checking for a root cause if any. Any help appreciated.

I got my question answered today. The holes are to balance the flywheel and don't affect the internal balancing.