If you would please Google " Led Circuit Wikipedia " and scroll down to " Polarity " it may better explain my statement.
Sorry that I can't post the link, I just don't have the computer savvy nor do I have the electrical knowledge to explain it better.

The Terralux bulb has a voltage rating of 2v to 9v so would probably work just fine with a generator and fluctuating voltages. The Tektite bulbs are voltage specific and probably would not .

I use a 6 volt battery for power and was told if the polarity is reversed the bulb would be toast. Everything I have read suggests the same. More than that I don't know.

I also have vintage lights and I use the screw in led replacements. Can't beat them.