Ah Ha! after a bit 'o research, it appears that there are two types of keys: those for use with Comfort Access and those without. Comfort Access keys are *not* rechargeable, whilst Non-CA keys are. My key does, in fact, have a removable battery and no "terminals" with which to charge. (unless the regular fobs use induction charging, which I doubt)
I'm pretty sure that there is probably something similar for all the other info, but I don't know... yet.