Westworld (HBO)
I agree with you, but neither option explains why he can't be harmed by the bullets. The employees are concerned about the androids hurting a guest, so him simply being a human wouldn't make him immune to being shot. Also what was it about him that triggered James Marsden to actually shoot him if he wasn't an android?!!!!
Answering both with "I think," so TIFWIW:
To the first part: I think the guns aren't firing real bullets, and instead some signal/pulse that triggers a squib inside of the hosts. IIRC, the movie mentions something about this, and how the guests don't have to worry about accidental (or intentional) human vs human harm.
To the second part: I think Marsden shooting at EH is symbolic. It shows the hosts are developing strong emotions/attachments they weren't programmed to have, and are becoming sentient. Marsden reacted in a rage without following his protocol. His puzzled look after shooting was more "Oh my God I just shot at a human," instead of "why isn't this guy dropping?"
*I think EH is purposely wreaking havoc in WW to elicit these malfunctions. If he's working for a competitor or what I don't know, just a guess. EH wanting the code on the scalp made me think that.
I'd love to hear your theories.