1972 C10 Gas Cap

[BT Classics]

I've searched the forums and now more confused about which gas cap to use on a 1972 C10. I purchased the Stant 10623 as it was recommended in another post and it doesn't fit. Should it be Stant 10742 instead?

Took the '72 out for a ride and it died. Noticed the fuel filter was clogged with what looked like fine rust. Cleaned it out and it ran for a bit and did the same thing. It hadn't been out for a few years and had old gas. After I limped it home, I tore it apart and the gas tank developed some internal surface rust. I pulled the sending unit and the screen and brass float were completely disintegrated. Drained the tank and used a kit to clean, derust and seal the tank. Just got it all back together and it is running a lot better, but noticed the rubber in the gas cap is all broken. The cap also doesn't really tighten like it should, which led me to a gas cap search.

It is an EEC tank. However, when I traced the lines, the vent line terminates in the frame rail in the engine compartment and has a bolt stuck in it. I discovered the original charcoal canister behind the battery and nothing is hooked to it. So from my reading on here - if you have EEC, you need a non-vented cap. But if you have EEC and it doesn't vent, you need a vented cap. I bought the Stant 10623 as several people on here with '72s are running it. However, it didn't fit on my gas filler. The one I have now fits loose and looks like the one in this post but the first comment was:

It's not the right one. The correct gas cap only has the 2 tabs like the 2 shallower ones. The other long tabs are for a passenger car.

So my questions are -
Should I connect the vent line up to the charcoal canister (I have no idea if the canister is any good); take the bolt out and let it vent in the frame rail; or leave it capped off and use a vented cap?

Which cap(s) will fit a '72? (part number) I've been looking and gas caps say conflicting date ranges: 1938-1971, 1947-1970, 1967-1970, 1967-1971, 1973-1978, etc.