King Arms M3 taclight

[Gridlock]

So I just recently bought my M3 light. After testing it I re-boxed it, but pulled it back out to show to a friend (curious about the brightness). When I went to put the batteries back in, it looked like the negative terminal spring on the inside was missing. I put them in anyway and the light works.

My only concern now is that that spring might be important. I don't want to short out a brand new light. Can anyone with a KA M3 confirm that there should or should not be a spring on the inside for the negative end of the battery? I can't find a spring, but I'm sure I remember seeing one.

tl;dr Should the M3 have a spring on the inside for the negative end of the battery?

Edited for conciseness.