I wouldn't use it........... this is typical "throw away" regulator. Crimped together, they are fixed pressure and non-serviceable. Run down to Ace, Walmart, or whatever hardware store is handy and pick another up.
The regulator probably works fine, and presumably you are using a fairly long hose, so the chance of the leak catching fire is not high..... It's probably been leaking for a long time, and you didn't know it. A spark will set the propane alight on the outside of the regulator giving you a small tongue flame, which ultimately could get the regulator hot enough to cause more serious problems........... as in a large flame. A situation nobody needs to have to deal with for the cost of a regulator.
Considering the fact that you are using a modern barbeque bottle with it's flow control valve, it should shut off instantly if you draw too much gas.......... a good safety device for barbeque bottles....... A nuisance considering the way I use propane............ I really wouldn't want to test it.
H.W.