Both shapes - Barrel and 3 Rib are 100% correct on a 1970. Except on a Hemi (which generally used the 3 rib and not painted). They were always painted on the engine. Any of the pics above that show no paint on the PCV or the grommet are a replacement. 2 different vendors - both show as correct in all engineering documents and I have original cars with both types - and have seen a myriad of others with both types.