Flights are booked, and they booked as a single PNR and a single ticket. On AA.com though my flights are grouped as TYS-CLT-LGA-DCA and DCA-BUF, looks like it may have been ticketed as an open jaw RT?

I expect I will have to ask the agent to send my bag all the way to Buffalo rather than to DC when I check in, but that appears to be within their written policy as far as I can tell.