Hate to break it to you but you would be surprised at the junk in your case.
No there's not. Been there, done that, got the tshirt (Mine pulled threads out with the plug). There is a pretty good lip at the top of the thread. The thread is 1/2-28 I was thinking but may just been -20. the hole that actually goes through the pan is only about 1/4" Helicoil is easy way to fix it, just jack it up and drill slowly. Poured a quart of ATF through mine just to see and it was perfectly clean when it came out. Several thousand miles later no problems.
Years ago I had one that was striped out, had just enough bite left to hold the bolt in so I smeared J-B Weld around the head and just left it, changed out the pan before the next fluid change.