Rear Sprocket Help

I am restoring a 77 Kz750b with aluminum rims and need a rear sprocket. The old one is a Sprocket Specialist 38t with 170z stamped on it, I ordered a sprocket off of Z1 enterprizes but I have the 65mm hub so it didn't fit. All the sprockets I have found are for the 90mm hub. Do I have the wrong year rear wheel. Please help this is the last item to complete resteration. Thanks

I have contacted sprocket specialist with no help from them.

Can't possibly be the original wheel: they came with wire wheels only.

The wheel also reads 130-90-16. The B series 750 twins ran a 4.00-18 rear wheel, not a 16" rear wheel. Don't know where that wheel came from, but it's not your bike.