I would say your at the upper end of the timing chain and gears lives.
I would change both, plus you will have a balance shaft chain and 3 gears for it as well.
The guides I have seen and used in my 1991 B2600i trucks have ALL been steel backed.......steel cored really, they look like they're plastic but they have a core of steel. Two of them.......left & right.
The balance shaft guides are steel backed as well.......three of those....left, right, & upper.