I know this is old, never saw an answer to the OP question. There was a site up called "youngbloodjetboats" that had all the history. It is no longer available unfortunately. I bought a 1984 TX19, it has a JBX HIN number on it, JBX's are Jimmy Johnson built TX19's. There have been over 15 companies who have made TX19's. On the site it stated that only those that were made by Youngblood, were called Youngblood TX19. All others are what ever manufacturer TX19 such as CP TX19, Condor TX19 etc. Originals came in 3 weights, 325, 375 and 550 lb layups. It's a shame that site is down as it had great info.