This morning, I got word from a TH-cam channel that one two-pair set had its front heads repainted into the newer yellow head livery inspired by the new HR4000 subway cars. While on the way home after a long day on campus, I found the set.
The livery looked weird, but awesome at the same time. The A650s (both DC and AC Series) have had their original red-white-blue livery since the 1990s. However, lately, their paint has deteriorated after years of neglect, making them appear in bad shape, so they decided to peel them off and retire them. Fortunately, some cars still have their original liveries intact, but only time will tell if they will ever stick around until they retire.