Without any information on the source of the knife (what made him think it was a prototype in the first place? You say it's sterile so I'm assuming no markings at all?); so let's say I found that knife at a flea market or pawn shop, I would think that it's 99.9% more likely a cheap knife that resembles a Spyderco if it has no markings. The chance of it being worth more than the value of its metal is very slim. If there was a reason to assume that it might be a Spyderco Prototype (like someone told him that, or there is a picture of Sal Glesser holding such a knife), it might stand a chance - but with no additional information, I'm wondering why he even thinks it might be a prototypefor a major company?
This reminds me of a thread a guy started in the Bernard Levine knife ID forum. He had a crappy knife with stag handles, and kept wanting to draw an association with Bo Randall (it went from being "ANybody know anything about this knife" to "Maybe it's a model 7 prototype"). I know that if you own an unknown knife that you want it to be as rare and valuable as possible, but the chance of any unknown knife being a rare prototype are exceedingly slim. I just told my Grandma today that an old aluminum or steel handle Imperial knife she found was probably not worth anything. Now, I can't say with 100% accuracy that it's not, but the odds are not in her favor.