A bow was built to be shot. If you did not have to pay a fortune for it , then go ahead and shoot it! Experience what it was like almost 50 years ago to carry and shoot what was then state of the art. In reality there is not that much difference from what is available now! If it makes you more comfortable put a little itsy,tiny,teeny,bit of super glue in the crack, try to keep it just in the crack and not all over the limb and it won't show. For the most part if the crack is vertical in the glass and doesn't go to the edge or doesn't start at the edge it should be OK.