This year's theme is "The 1980's"
means that the model entered into this category
should be a replica of something seen or used in the
1980's or in a 1980's produced TV show or movie,
even if that TV show or movie showed things done in
another time period, such as "Raiders of the Lost
Ark" which depicted pre-WW2 subjects. You have to be
able to tie it into the 1980's somehow in a