I just buy all the ones that look similar. Longer, shorter and fine and coarse. The left-overs go in my coffee can of 'bolts about that size'. Over the years I continue to use up the 'strays' and I just can't keep myself in bolts. I know sometimes I waste 5 bucks doing this, but it's a 24 mile round trip to town, so anyways, it's just what I do.
According to my book, it is 7/16 x 14 x 1 3/8! p/n 20450-s b-106
IIWM like GB says I would pickup some fine and course thread 7/16 bolts of different lengths, you can never have enough nuts and bolts.
book on e=pay is ~20.00