Looks like you're on the right track, Carl. The rotor is the most common part to fail in the charging system, so it's not particularly surprising that's the fault. We were hoping it was just the brushes, but so it goes.
By the way, you might consider getting a set of Rick's alternator brushes while you're at it, and stash them in the tool tray. His attach to the mounting lugs for the spade terminals rather than soldering. Soldering them is someing of a PITA considering the whole stator has to come off, and one of the retaining nuts is almost impossible to get at. Gotta wonder about those guys that invented coocoo clocks!