There was a general re-issue of dealer plates on the blue plates, probably in 1982.
Plates are listed in alpha order as issue dates do not correspond with prefixes for dealer plates.
DL, DM, DN, DP, DR, DS
Factory repaint on top of tan base
The first plate here is a repaint of a dealer plate on the previous base ... notice the dash instead of the NJ map.
The other plate is the "real" 1979 base DLK-744