The 767-200s are undergoing some refurbishment, at least to the F and J cabins, as indicated here.

The 757-223s AFAIK only go through refurbishment during the heavy C checks?

"Narrowbody "C" Checks
American does two types of "C" checks on its narrowbody planes. The first is a "Light C" check, which occurs approximately every 15 - 18 months. It requires approximately 2,100 man-hours and three days to accomplish. Every fourth "Light C" check becomes a "Heavy C" check. This check requires 20,000 - 30,000 man-hours and takes from three to five weeks to accomplish."