Geezer here, concerning Jayhawk Archery. Years ago, when I started making medieval crossbows, I bought my aluminum prods from Jayhawk Archery, then located in Oklahoma. After a few years of production, I got a notice from the mom and pop outfit that was Jayhawk that they were going out of business. As I recall Pop died, and mom was doin' poorly, as the old folks would say. (This would be @ 1983 or 84) They were looking for somebody to buy their tools, sales lists, etc. I couldn't afford to buy them out, but I did buy the rest of their in-stock prods. Eventually, I heard from the new owners of Jayhawk, but in the interim I had started making my own aluminum prods. Nowadays, I buy my aluminum prods (it's 7076-T6, in 190 thousandths of an inch, in case you wonder) from Darkwood Armoury in Mississippi. Their prods should drop right into you old Jayhawk kit-bow, though they're not made with a hole through the middle. You'll have to do that yourself. Geezer.
ps: there was another company making a similar product in Petaluma California. No doubt they're long-gone as well. Geezer