Egads! The 22nd? You're cutting it close!
I have tried a BB before. I had drilled a slight dimple before the barrel was cut. I thought that dimple would be fine for a BB and some super epoxy. I was wrong. The BB will stay put for a few rounds, then disappear.
If the rib is still on the gun, it should be easy. Get a small screw, say a 4-40 thread, a 4-40 tap, and the appropriate drill bit. These should all be available at your local home supply store (Lowes, Home Depot, etc). Try to find a short screw, at least one that will bottom out against the barrel and not stand very far above the rib. Drill a hole and tap it. Clean the area thoroughly and remove all oil and debris. Put a drop of epoxy in the hole, put the screw in, and your done.
If you look very closely at these pictures, this gun has a stainless 4-40 thread screw instead of a bead
What can I say? Necessity is a mother. I was going to put a proper bead on it later; I have several beads for it, but don't have the appropriate tap yet. I've gotten used to the screw sight, and really don't see any need to change it. It works, and that's what matters.
The 4-40 thread is common and small. Later you can drill the hole slightly larger, re-tap, and install a proper bead. All of the stuff for a proper bead are available at Midway or Brownells.
I'm not a huge fan of TruGlo. I've tried a couple of their snap-on sights for non ribbed barrels. Both of them cracked and flew off the gun after some shooting. There are a lot of add-on sights for ribs that can be ordered from everywhere, but since time is not on your side you can look at those later. Unless, of course, you are fortunate enough to have a good store withing driving distance like Cabelas, OutdoorSports, and some of the others.
Hope that helps.