I loctite the vents in, as they should never come out, except when I am are going to replace it. That's the Chambers style vent.
Breech plugs should be a good fit regardless of your method. I anti seize the threads lightly.
I used to gob 'em up pretty good, but found when I went to brown the barrel, the anti would weep out of the joint on the top flat and cause that spot NOT to brown. So now I work a little on the inside threads, and avoid getting anti on the standing faces of both barrel and plug.
I like Long John's using loctite on the plug as well, as just a little heat will soften it up. Loctite won't weep out when browning.