The big rusted bolt on the right bottom side of your engine is the older style chain tensioner.
That one had a flaw, that the oil path could clog up, and was replaced with a new style one.
Recognisable by a little bulge on it.
With the old style tensioner being there, it makes me think you did not have a chain swap done. (GM advises 10 years or 100k miles)
Keep in mind that after a small 20 years, the plastic guiders are known to get brittle and fail, regardless of how few miles it did.
If the guide fails, the chain can swap a notch on the cam shafts resulting in potential engine damage.
Another fun one is the ecu location.
The left side of the gutter perfectly guides rainwater into your ecu location.
I have build a little roof on top of mine for this. You may want to consider the same.

Edited by smiley, 08 December 2020 - 10:27 PM.