Is there any sort of source for tracking the differences between the different years of Gretsch models? As I browse different listings I see the years listed for them, but it's not totally clear what changed between them. If it helps, I'm browsing for Setzer Hot Rods. I know not all of the early HR models had TV Jones pickups, but at what point did they switch to being standard? Seems like the body depth fluctuated a bit over the years as well. Any other big differences between the years?