Credit shall be granted for the amount of tax paid to another state on a motor vehicle purchased in another state at the time such vehicle is first registered in the Commonwealth, provided the purchaser provides proof of payment of such tax. However, no credit shall be granted for any tax paid to another state if that state exempts from the tax vehicles sold to residents of a state which does not give credit for the tax. Credit for taxes collected under the Virginia retail sales and use tax (§ 58.1-600 et seq.) shall be allowed against the tax levied for specially constructed or reconstructed vehicles and other motor vehicles subject to such tax.