The DMV distinguishes between motorcycle, passenger, and truck dealer plates, but there seems to be little difference between the passenger and truck plates. I have not spotted any motorcycle dealer plates yet.
Dealers seem to have some latitude in moving plates from one vehicle to another. Note the marks on [3959 DL] below. These marks seem to be evidence of a variety of methods for attaching the plate to vehicles.
From AS 28.10.181:
(j) Vehicles owned by dealers. A state-registered and bonded vehicle dealer may apply for dealer registration plates. A plate issued under this subsection may be used only on dealer-owned vehicles during the routine and normal course of the dealer's business, excluding service vehicles, or for transporting an unregistered vehicle from a port of entry to the dealer's facilities or from one dealer to another or, in the case of a house trailer, from the retail facility to a trailer space. A vehicle permitted to have dealer plates must be affixed with two plates issued under this subsection. If the dealer sells or transfers the vehicle, the dealer plates may be used on the vehicle by the new owner or transferee for a period of not more than five days after the sale or transfer. The department may seize the dealer plates if it has reason to believe that the plates are being used to defeat the purposes of, or are in violation of, this chapter.