jockey wheel pulley bolt

So I was cleaning the jockey wheels and lucky me one of them fell down and bounced onto the floor and rolled in the drain :evil: :shock:

So I am using a water bottle bolt, which is also M5 but it is a tiny bit shorter (probably a mm less) whilst still holds it together it doesn't protrude slightly like the proper ones. Is this ok? Should I get a proper one? or a longer one?

Cheers,
Gabriel