I haven't and I'm no expert but I'll take a stab at an explanation.
If you look at the stamps themselves they are the same on both components. Even the strike force (depth) is similar. That tells me the same person did all of them. What that also suggests to me is perhaps at one time, someone took the assembly apart and figured to be safe they had better mark the carb's and stay plate so as to get everything back in the right spot. Just a wild guess on my part.