RARE Harley Davidson motorcycle antique photograph with labeled parts

This is a really rare one of a kind vintage Harley Davidson black and white photograph; I am not sure if this was part of a show, or a class - I am not a Harley expert; so please let me know if you can tell what year or what style Harley this is; each part of the engine has a label on the ground; it is sealed behind glass and I don't want to take it apart; measures 5" x 7" - an incredible gift for your favorite Harley guy or girl.