The extractor rod seems like it screws into a plunger in the lug to lock the cylinder in place? I noticed because it wouldn't open and I screwed it back down and it opened. Is it supposed to do that?
No, it's not supposed to do that. I guess the plunger rod is loose. What probably happened when you screwed it down is that it pushed the latch out of the way. Pushing the latch forwards should allow you to open the cylinder.
It looks like a three screw Model 10 with a heavy barrel.
Put a drop of blue locktite on the threads and screw it back in. My 686 used to do that too.
Also, do NOT use pliers on the plunger rod. You WILL 'booger up' the plunger rod.
Agreed on using BLUE Locktite on the threads, however, I'd like to stress that you should put two (2) EMPTY cartridges (opposite from each other) in the cylinder, when tightening the plunger.
Putting two (2) empty pieces of brass into the cylinder will help prevent breaking off the locating tabs under the extractor 'star'.
Also, do NOT use pliers on the plunger rod. You WILL 'booger up' the plunger rod.