Thanks to everyone for helping me.
There is a dealer right down the street so I figure to go and get one bolt when the valve cover gasket arrives.

I'm just happy that today it finally passed the emissions test - I was getting afraid I would have to get rid of it because even though I'm not looking for something for nothing, I haven't found a decent mechanic who charges anything close to what I think is reasonable. And I hate it when they start replacing parts by trial and error and running up a big bill, giving me that old story "well, even if you don't notice any improvement it did need that work...."