Save yourself a little grief.
Find a reasonably accurate thermometer, digital cooking, candy, something like that in the right heat range, and put it and the stat in a pot of water. See at what temp it opens. Put the one you took out in there too, so you can compare.
If the new one opens about right, lift it out with a fork, let it close and pop it back in. Do that a few times in case it only works the first few times.
About 10 years ago, someone released a batch of bad ones. I was lucky and found out about it in time from some of my friends who had had to change theirs a couple of times.
I put the new one I was about to install in a pot, and it had not opened when the water started boiling.
My local NAPA guy was a fishing buddy. We hooked up a hot plate in back of his store and boiled stats until we found a good one.
J.