Right, JABO for the first and newer MK for the second one.
Production run was what JABO made for their normal production. Their normal production consisted of industrial application marbles and also swirls for marketing to toy stores and Walmart, etc... This was one of those. JABO tried to get more for their marbles from Walmart and lost the contract and pretty much closed their doors, but the investor runs saved them from totally closing. Investors (often marble enthusiasts) paid to run marbles and those runs normally lasted a day or two and each run was named.