V-Fins or Butterfly fins

Hey, I'm new around here & not a surfer myself but, I recently rescued 2 separate v-fins from the garbage heap & I can't find much info about them! The fellow they belonged to was a "hanger on" at Dale Velzy's San Clemente shop during the 60's/70's/80's so I'm pretty sure they're Velzy (Fran Velzy "thinks so" too) but I'm wondering since what little I have read being so positive why didn't they ever catch on? Do they have any value? Some guy offered my $10 for both - that seemed like an insult...???