Here's what I figger. Take my word with a grain of salt.
Pretty much ALL bows are production bows. If its made by a bowyer at a shop, for the intent on selling to someone, then its a production bow.
Its just that there's some production bows fit like it was custom taylored to your hand. Like its an extension of your arm.
Someone mentioned the words "assembly line". I was at a bow factory recently that we've all heard of before...there were 3 or 4 fellas in there working on bows, and each one had a specific task that had to be done before a bow got shipped off to its new owner. But I wouldn't go so far as to call that an assembly line...that phrase brings about a negative feeling, of something thats made cheap, quick, and without much quality control. And this company definitely does not fit that description!
In my opinion, the only true custom bow is a self bow. And then, its only custom until it gets sold to someone else. (Unless its built for that 1 person only)