From what I understand, once a ticket has been a "e-ticket" it will show up, both online and in printed version as saying "ETKT" on the actual paper tickets. If issued as paper, and never changed, it should not say ETKT. However, if orignally issued as ETKT, even if briefly, before being printed as a paper ticket, it will say ETKT and actually be a paper ticket.

At least, this is my experience, and the explantion I was given by a senior United Check in agent.

Billy