2536771 CAP 4BBL Intake Manifold Port Plug ?

I picked up a standard 3/4" sae bolt today, it is just a bit smaller than the 1/2 pipe plug and it screws right into the port. I have a guy that is looking for a plug that size with an o-ring on it because if you look at the top of the port you can see the small embossed area, a flat washer type gasket I don't think would seal it off. If he does find the plug that I need I will take a picture of it before I install it and list the size for anyone else who is going to have to go through this.
Bob