Tom Archer, if you are still following this thread...is this also the highest serial you are aware of still called "Hollenbeck?"
Sorry for not paying closer attention to this thread gentlemen; but the answer to your question Nick, is that I don't recall having ever seen a SAC made Hollenbeck marked gun numbered higher than yours. Years ago when I was really deep into SAC research I noted several significant changes to the gun to include the name; but with the limited availability of study samples and literature, took some liberties to make approximations based on the samples I did have. My estimation that the production of Hollenbeck marked SAC guns ended at around serial number 5,000 was based on a Grade A gun I owned that was numbered 5,044, coupled with the fact that the highest numbered Hollenbeck guns I'd located to that time were in the 4,8XX range. I made other serial number/production approximations such as when the SAC gun transitioned from the First Model to the Second Model, the Third Model etc.; and in all cases the years since have revealed that, although my approximations were close, there was overlap in the various transitions with examples found having early and later features (and a few examples having features from all three periods?). I've even discovered an entirely different transition model between the Second and Third Model SAC gun as regards an entirely different cocking device; a design which seems would function with guns having manual extractors, but would not be conducive to guns ordered with auto-ejectors. Perhaps that is why I've only located two examples (both in the 34XXX serial number range)? Glad to know there are others who appreciate these old relics from America's gun making history; and feel free to give me a shout anytime you wish to discuss SAC guns further. Thanks, Tom