some old jeeps and IH's also had left hand threads. Usually, if you can see the end of the stud, the lh ones have an "L" stamped on the end.
Yes, the studs might break, and one could try penetrant and repeated rattling with the impact and hope it comes off.
However, there's a 90% chance that they're junk anyway.
In this situation, they're usually either:
1. Overtorqued, which has potentially stretched the stud, and should be replaced.
or
2. Corroded, and they should be replaced.
or
3. Cross threaded, and they should be replaced.
Not only that, but in the time you spend trying to get it loose, on 90% of cars, I can snap it off, put the new stud in, and have it back together by the time you get it loose and find out it's shot anyway.