It is not really an "odd" cancel and yes it is a first day of issue date. The Post Office sets up first day of issue ceremonies at different places around the country, including major stamp shows. In this case, the Post Office set up the ceremony at NOJEX - the North Jersey Federated Stamp Clubs Exhibition which in 1991 was held in Secaucus, New Jersey. Stamp dealers typically take advantage of such events to make up first day covers using the stamps issued along with the show cancel instead of the standard Washington D.C. first day of issue cancel which is what you have here. That day there were two stamps issued - the truck one (which your cover has on it) and a canoe one. Unfortunately the stamp dealer who manufactured your example did not bother to make up a nice cachet and the recipient roughly opened it along the bottom.