Google some of the Knife Forums for Blackie Collins knives and see if you can find pictures of his folders like yours. Some of his knives are one of a kind custom made. Values can be high, depending on condition, etc. Ed.
I have the same model - given to me recently. I believe it is the model #6060 and you can find the serial number if you open the blade and look inside - it's engraved on the brass liner.
I've been looking for a sheath/holster for mine and have seen knives going for north of $100 for NIB with papers on Gunbroker and eBay (one currently listed).
They are a beautiful knife, mine is a keepsake. Enjoy...........