I know this is probably a noob question but... I was wondering about the trademarks, I looked on some sites and the WE has trades and some don't have any. Do WE's have trades or do they not? It looks like the AFC version does but what is the difference? Does it only accept CO2 or can I use propane? For criteria I'm looking for a CQB length, with trades, an RIS, and take green gas.