Valve covers / twist on or push in rubber cap??

[TBONE1964]

Tyrying to figure out what has what and what is correct. Some say 73 and up for the twist on metal oil cap and others say they have it prior to that from the factory.

My 72 is a Cheyenne with a 350/350 turbo with A/C and power brakes. It has the oil fill extention tube on the drivers side rear of the valve cover. The passenger side valve cover has a push in oil plug that say's "oil" on it. The A/c compressor covers it and it is not accessible to pull out and use as a fill location with the A/C compressor mounted. My A/C compressor is not on the truck now but it will be soon.

If your truck is factory, chime in and tell us what you have.