You are probably right. I have never seen that type of one-sided bent-style knives all supported by a common rod inside (apparently.) Alternating rows of left pointing vs right pointing. Pretty interesting design. Like you, I am guessing it is pretty old and not something currently sold. And for sure if he is going to use it he needs to come up with castor wheels of some kind! [A whole lot cheaper than adding a roller.] The post holes are still there and look serviceable -- probably just a matter of measuring the diameter of the holes and searching around for castor wheels to do the job.