Help with ID on Dupont lighter

[lunarose]

Hi, I have this Dupont lighter that I am 99% sure is authentic, the gentleman it belonged to (my cousin's husband) passed away in '89 so it is at least 24 years old and I imagine fakes were not so much a problem back then. Is it a Line 1 or 2? I do not have papers or a box. What would something like this be worth? Any info would be great help its serial number is BU1439 it has 20u does that mean it is 20k gold? The cap at the bottom has a slot.

Thanks,

Nancy