Good eye, Jim. You're right, I should have followed with 'chassis' all the way through.
In any case, I took both of them out and found that the little punchout numbers for month/date were both punched as 5/2014. They were covered by the tie-down straps and big cables til I removed everything.
My luck has always
held that if I buy 3-year batteries I'm gonna get 36 months, and the same with 48-month or any other combination. Guess you could say I got my money's worth this time (72 months!
) . Therefore, I'm off to the battery store for 2 new ones.
Thanks for y'alls inputs, I knew I should replace both, was just trying to 'cheap-out'.