Are you sure that’s what you want? The face sealed manifolds, e.g. those with the angled output, do not have “plugs“. It’s not just that the plugs for a modern manifold won’t fit. Being a face seal, that’s not really how they work. Like
@guruboy said, it’s not impossible to seal them, but it is impossible to buy a properly designed and manufactured part for that job.
Without actual details of what you’re trying to accomplish, I have no idea if that is actually a problem for you. My suspicion is you’re trying to do something like sidemount with 7/8 tanks, and you want left and right valves. And if you don’t mind taking risks with high-pressure gas, etc. it might be possible to do what you’re looking for. But it isn’t something that you’re going to be able to walk into a dive shop and get filled if anyone looks at all at the valve.
And if in spite of all of that do you want that manifold, or if my assumptions are wrong, that’s fine too. I have such a manifold, but you have to buy the tanks that are attached to it as well!
They’re for sale, but it’s a long way to go for a couple of valves.
I just want to make sure that you understand the limitations of the face sealed manifolds that you seem to be asking about. If you are, that’s great. Hopefully I won’t be diving next to you win something lets go…