I'm flying SEA-ORD on AS and then connecting (on same ticket) onto an AA flight. I know AS will through-check my bag, but can they check me in for the AA segment and print my BP at the counter at SEA?

If not, can I use OLCI and print my own BP for the AA flight before I leave home (and thus before I check in for the AS flight which will precede it on the same ticket)?

Thanks in advance for info and insight.