The dress at the heart of this story and all those shown in the "1979 newspaper wedding photos" Jennifer views in the library, are strapless. In fact, that style wedding gown was nearly unheard of in 1979 and, according to fashion site racked.com, the strapless trend only began to emerge in the mid 1990s, at least 15 years after the movie nuptials were supposed to have taken place.
Watch carefully as Jennifer's car changes between a blue Ford Edge and a blue Ford Explorer. Stock footage used for establishing Jennifer and Danielle's store front show the Ford Edge. The close ups with Jennifer driving and her standing outside the vehicle, show the Explorer.