Ay up.
Could do with posting a photo if poss.
I've seen the assembly when we cast our eye over it in your workshop. I've no knowledge of the dominator specifically but maybe there's a few checks which might help.
I don't know how far into the hub the machined portion on the carrier should go. From memory, is the spacer in the carrier actually a bearing with an extended inner race? If so a check on the part number would clarify it is the right one. Next check is that the bearing in the carrier is fully home. Next we could check the assembly when fully tightened up to see if the bearings in the hub are actually fully home and contacting whatever spacer is between them. A visual check on this also. (Check the wheel spins freely) Next we could measure the "vanes" to see how far they are protruding into the hub. See if it seems as though they should go further in.
If you have full overlap of vanes into rubber, everything looks/feels in order once you've nipped up the spindle and all the bearings check out to micro fiche, then I'd think its fine to go with it.
I can't imagine the machined portion is actually a "fit" into the hub, but just that the casting is "cleaned up" concentric to ensure there's no contact with the hub. But, yes, you'd expect it to protrude inside the hub to help keep rain/muck out. But I don't think they'd design it to come too close to the hub either.
