Gunsmithing Need help with Polymyr 80 percent lowers

latinaincovina

Sergeant
Full Member
Minuteman
Mar 14, 2012
144
0
West Covina CA
I bought 80 percent (tan - they were out of pink!) lower receivers and they need to be finished now. They are plastic and look very easy to complete. There is a black center that looks like it was pushed in. Does anyone have any experience with these that can point me in the right direction?