I'd highly recommend you have it tested by a professional to see if it's safe to use. Newer canners have safety features, like a melt-away plug if the pressure gets above XX.
Can you post a pic? Is it a guage or a weighted canner? You should have it tested, regardless. I think your local county extension can do that for you.
Lucky you, finding 200 jars! I've got about 120-140 but my supply mysteriously disappears as I give away gifts.
Note to self:
1. put...