I've seen "endless legroom" exit row seats (which are generally classified as MCE for reservation purposes) on some other AA planes too. Not sure if they're current configurations, or only early configurations (on A321 non-transcon, I think). Oh, and one of the two-aisle planes (that predates the 787 and Airbus models being used by AA) had infinite-legroom exit seats too.

But there is no average to bump that I know of. They just publish a range, and the top of the range does not include special cases including bulkhead-less first-coach-row and "true" exit row seats (especially the "endless legroom" variety).