Hmmm...I'd say if it's been a year, and it doesn't seem to bother him in the least, and there are no signs of swelling, infections, etc., then it's probably fine.
Did he not go to the Vet once he reappeared after getting caught under the hood of the truck? Does he ever go to the Vet? As a senior, it's always good to have a Vet visit once in awhile just because seniors are prone to "issues", including tartar build-up, which can cause other health issues. THEN, during your visit, you can point out this toe and just make sure nothing untoward is happening with it.