1812 is before Andrew Jackson, who successfully won a battle against the European Bankers. He was also the first President to have an assassination attempt on him. The guy's guns misfired, and Jackson started beating the crap out of him with his cane. 1812 is just a few decades after the founding of this country. Going back even earlier puts a whole new twist on all of this and precisely how old some of these KGC marks may be and what folks like Jesse James were doing - maybe not as much stashing and more relocating/recovering and spending going on during his time, following up on older reports/rumors/maps. Merely speculation on that last part, on line of many I can see if your research is ultimately correct. That would be yet one more game changer for how to approach and research all of this stuff, for 'KGC' research could really start pre-1776, in the traditional KGC sense.
I think expeditions out to the west, namely the folks who ran them, like Pike, Frémont, et al, are people to look into and question their activities. I haven't made the dive into them completely, but I think a lot of those reports from those early expeditions to be important things to study carefully and see if there are things to be read between the lines.