Looks like the latest video for the UNICEF is online and it reveals a noticeably older Chewie! Unlike that image a while back we thought he'd look like (in there I didn't think he was "aged" enough), here his eyes look aged with more white around on his face, just like how an older dog would show age - I think he looks perfect now.
http://www.slashfilm.com/j-j-abrams-thanks-star-wars-force-awakens-set/