A good way to tell if it's a 47-50 or a 51-55, is look at the driver's side cowl panel. If it's flat, you have the later model years. If it has a side door that opens up for extra air flow, you have a 47-50.
Maybe this will also help
https://scontent-b-iad.xx.fbcdn.net/...89428322_n.jpg
This facebook group has a whole lot fo information on it. I'm sure you can find everything out by looking through their pictures.
https://www.facebook.com/media/set/?...3839374&type=3
Hope that helps,