I missed your question.
I did one of each actually (plastic and poly).
The plastic was demilled due to out of spec fire control part pin holes being out of spec.
By demilled, I mean it was torch cut and melted.
The aluminum lower however, turned out correct and proper and like it should've.
But there are differences in the lower jigs.
Whichever jig you get, make sure the fire control pin hole markings are on both sides of the jigs rather than the jigs that only have holes on a single side only because the ones that just have holes drilled on one side, you can easily use that hole, but the bit not be straight and cause an issue of it not being perfectly straight when it drills through both sides of the lower.
If you notice, this one is bad and only has the trigger/hammer/selector hole on one side of the jig
This one has the fire control holes on both sides of the jig and is the better style to use. It's a few dollars more expensive, but eliminates hours of work lost and a billet wasted.