I almost lost mine as well, a month ago. Upper bolt was missing, and had been for awhile, and the lower was half way out. The first time in 5 years and 2 starters. I changed the starter exactly a year ago.
Just wondering what would have caused this. I red locktighted the bolts and so far so good.
Its interesting, and it may just be coincidence, but all of you have 2002 trucks with the exception of dcf4x4 who has a 2000. However, he has replaced his starter and since locktite has been good to go.