Ahh, I see they dug in PMN and SM701 mines after removing the SM70s. So, the West Germans just helped them modernize their minefield. While the Czechoslovaki border went unmined. Considering that each force should have several million landmines in stock and that to effect a 1/3 mi sq you'd need <5,000 mines I don't see how allowing engineers to emplace mines in a timely manner should reflect on supply. I'd say 10-15 percent chance.
The pillbox/bunker as a unit idea would just add flavor. The 1000s of 'observation posts on the East German border would be used as pillboxes in a shooting war. They were more like bunkers down in Czechoslovakia. Then again one could use blockhouse/fortresses as defensive positions for housing units I suppose.