I Believe that the number is somewhere closer to 100 than to 300.
But that assumes that the total number is represented as a value compared to the numbers that I have seen owned or sold in the last 9 years.
So, make up your own number, say that you have seen 35 total in the last 9 years and figure that in the time 20% to 30% have been publicly resold, follow each knife to make sure you are not counting the same knife twice.
With that figure you might project 175 down to maybe 100 or so made and sold back between 1996 and 2001, of this particular model(the one of three hundred)
Just a thought, work out the formula that makes you happy.