Mercruiser Alpha One Prop Installation Question

[UtahBoating]

Help school me on the prop fitment. Alpha One drive. The first pic is the prop I have been running. I damaged it so I took it off the boat. The guy I bought the boat from last year gave me an extra prop but the hub looks different. The next pic is the spare prop and there is a insert that fits in the outer side of the prop. The last pic shows the inside of the prop. Is there supposed to be another insert for this side? The spare prop seem to fit with just the one piece but I don't want to do any damage. If I buy a new prop what should I be looking for as far as fitment goes. Both of these are 21 pitch and that seems to be the perfect pitch for my boat.

Thanks for the education!

 

[alldodge]

First and second pic appear to be props which will work on the alpha drive, just have different hubs. The third pic hub appears to be toast, no good. In any case need a better pic to look at. Tried to blow it up, but there is no resolution