Glad it worked for you. Yeah the bottom plate is really easy to take off on OM2.
You might wanna try dropping a tiny amount of oil or WD-40 on the thread and try to take the cap out (do this AFTER you take the bottom plate off the camera!), but if it's cross-threaded, it may not be worth the effort and better kept closed. You don't have to change the battery on OM2 often so maybe it's easier to just take the bottom plate when you do. If you are afraid of losing the bottom plate screw, drop a tiny bit of BLUE loctite on the screw. And be really really sure the screw goes straight!
off-topic: Wrenching motorcycles since I was 13, I had my fair share of damaged threads.
It's a bitch when you strip a thread of floating bowl on carburetor.