Can you snap an image thru a glass? Typically the mark on the lower rib is a lowercase Gothic/script g. The other marks may be Cavemen. I'm not sure that Wildmann/Hercules needed a staff and most images show a staff of sorts that has one end larger than the other & it is contoured like a club. Folklore has it Hercules killed a viper in the cradle, worked over a wild boar or 2 and may have slain some of his enemies with that jawbone of a jackass like Samson. I don't think he preferred a staff.
I'm curious if some have considered the U xxx an Untersuchungsstempel or inspection type number.
On the Sauer, I guess the principle of Ockham's Razor might be best and it is what it is upon face value.
Kind Regards,
Raimey
rse
