Books, strangers, and.... pocket knives?

Here is what happened: this fairly elderly guy with a gruff look walks in to the shop and stands in the middle of the room for a few moments as I say goodbye to another customer. Turning my attention to the man I greeted him and told him to let me know if he needed anything. He kind of shrugged me off and said he was just browsing; but he didnt really do this in a mean manner or anything, in fact he had a fairly polite air about him in spite of his outward roughness. So I went back to entering books and he walked around the store for about ten minutes seeming to be actively looking for a book that might catch his interest. But then he came up to me to ask a question which I assumed would have been your average "hey, do you guys have such and such", but instead he grumbled some vague inquiry about pocket knives and if we had any..... I was pretty confused and needless to say I felt weird telling a customer that "No, we dont have any pocket knives" when I work in a book store. The man kind of wandered out with a "thanks anyways" and I was left with a strange feeling of perplexity.... That is until later I realized he was probably referring to "us" not as just the bookstore as the market on a whole, which would make much more sense. Mystery solved I suppose, but it sure made the day interesting for a bit.