So the shop guy told me that they source their angel eye halo rings from a company called Morimoto. I did a quick Google search for "morimoto plasma LED" and was able to find this:
http://www.hidillusionz.com/services...ngel-eyes.html
So it looks like mine are indeed LED, and they output just like CCFL (cold cathode fluorescent lighting) style. For what it's worth, I have super old CCFL style angel eyes on my E46 3-series from back in 2006 lol.