Wanted 40-series Early 1F Oil Filler Cap (P/N 12108-60020)

I have this one. $45 plus shipping

Ok.

After looking more closely at your tube assembly, I had to do a double take and go out and look at our existing one. Sure enough, it is slightly different. It does not have the provision for the PCV but instead the PCV goes directly into the pushrod cover. See photos below. Interestingly, I don't se that reflected in the Electronic Parts Catalog as to when that change went into effect. Ours is an 08/1970 1F. I suspect that the filler cap would be the same but I'm unable to verify from the parts catalog.

By the way, I have the same slot & tab welding table.