Is this some kind of sick joke by the taiwanese kid that put these together?

How can I tell which one is + and which is - without killing it?

 

If they're LEDs, then they only will light up when wired correctly, so if they don't light up one way, flip the wiring and mark the wire accordingly. Its rare that it will damage them if you have it wired backwards momentarily. I had 2 white wires on my LED rings that I got for my projector retrofit on my blazer. Didn't work one way, so I flipped it and it worked, and I sharpied a line on the - wire