We bought our 5th wheel in Colorado and didn't pay tax till we registered in our home state of arizona. Never heard of it being done any other way, unless you are a resident of the state you purchase in.
When I went to buy my fifth in Indiana, I found out that Indiana and NC ARE NOT reciprocal states. Pay tax in Indiana and then again in NC.
However, the Indiana dealer drove it over to Illinois, about 6 miles awasy, and I took delivery there, avoiding the Indiana tax.
One needs to check their state laws to determine if and where taxes are paid.