Cam button / stock timing chain cover

Correct. A lot of the manufacturers used the nylon coated camshaft sprockets to reduce noise. It's always been funny to me how much they tried to make things quiet and at the same time make them way less efficient and durable. Just like hydraulic lifters. Only two reasons they came about. Noise and to eliminate adjustments. I've seen a brand new replacement nylon camshaft sprocket fail on the first turn of the engine. It was a long time ago, too and a made in USA TRW replacement set. We got a Cloyes all steel double row and never had a problem with it. That's something that they just never should have done.
I agree.