is the spacer missing from behind the middle idler pulley ?
glad you caught it before it went bang
I too was wondering about that.
I also note that the lower idler roller looks like the eccentric adjustable version used on X25XE/X30XE. However this engine is a Y32SE and these did not have the lower eccentric adjustment. Nothing wrong with using the eccentric, arguably it's a better arrangement, provided of course that the tensioner and rollers are correctly adjusted.
It might well be that somebody swapped the tensioner and idler roller from an earlier X30XE kit onto the Y32SE backplate. Again nothing wrong with doing so provided you don't forget the spacer and use the correct bolt.
Looking at the middle idler roller it seems to me possible that it might never have been correctly correctly adjusted. Or it's moved. Perhaps I'm completely wrong but I would have expected the corner directly above the arrow line to be somewhere around 9 o'clock, depending on wear. It looks to be around 6 o'clock.
So we maybe have a missing spacer washer and incorrect adjustment. Makes me wonder if the person who did this had the proper locking kit or understood how to use it?
And since you asked the question. Any decent kit for these engines will use SKF or INA bearings. Contitech, Gates, SKF kits are all widely availabale and good quality. A number of members
simply buy two of these AC Delco kits. This obsolete kit doesn't include the lower idler roller so you scavenge one from the tensioner/idler backplate in the 2nd kit and ditch the remaining unwanted parts. In the UK it works out less than half the cost of a full kit. And one kit is still less than the cost of a separate lower idler on it's own.