Benchmade Ballisong ID

I have a Benchmade Ballisong knife, approximately 27 years old that ones not have a model number anywhere
on the knife. Does anyone know how to ID the knife model, or have any suggestions on
an accurate place to look?
I am trying to determine the value of this knife.

Never carried, never sharpened. Like new.

Thanks for any help

I googled it. Here are some images https://www.google.com/search?q=Benchmad...858&bih=987

Thank you Billybob. I appreciate that info. I also have found pictures, but have not located
information on the value of an older BM Balisong.