Totally Stainless
Was flipping through my year one catalog for 64-72 Skylarks and it now has a GN section. It shows Totally Stainless:
Front Cover/Water Pump Bolt Kit. Stainless-steel hex-head front cover and water pump bolts. Part # TS5917 Buick 231 V6 $19.90 kit
Oil Pan Bolt Kits. Stainless-steel hex-head oil pan bolt kit for steel oil pan.
Part# TS5922 with steel oil pan $4.90 kit.