What you found is pretty typical of just bunging the belt on, setting the tensioner and calling it done.
Broken cover backing plates aren't unusual either. If you replace it, bear in mind there are two different types.
While you have the backing plate off is an excellent time to change the thermostat, as you don't need to split the housing from the transfer tube to get them off the engine
That isn't the (metal) backplate though. It is the (plastic) front cover & cable tray. My recollection is that the backplate doesn't come off until the cam sprockets are off
I think Darth Loony described the easiest way to release the thermostat:
- drain the coolant and remove the top hose from the transfer pipe
- plenum off and remove 2 bolts from thermostat housing.
- leave the bastard bolt in place for the moment
- use some BIG mole or vice grips on the body of the thermostat and keep working at it until it releases it's death grip on the transfer pipe.
- remove the bastard bolt and pull the transfer pipe out.