If that knife is in new unused condition, I'd say you made a great buy.
I have 2 of Allen's folders from past BLADE shows and I'd expect to pay at least $500.00 for one of his knives new....pre-when he gave up CNC and laser cutting or whetever else technology he was utilizing and went back to cutting his blades on a bandsaw., etc, and went completely "hand made" by him....by his ,and I agree, defintion.
Allen is a very creative maker with a lengthly future.
As a collector and as a maker, I would have no problem spending $500-1000, or more, for one of his folders depending on the materials, details and the price he is asking at his table at a knife show.