Prior to WWI, there were many options of available chamber lengths as well as New Primed empties for loading. The 3" 16 gauge was among them. Also, many custom loaders bought the primed empties & loaded them to the customer's specs. These often carried the name of the loader on the top wad.

Stan is your box of the older variety or a newer one. Also, is there any info on the top wad or just the headstamp & possibly side of the case?

Miller/TN
I Didn't Say Everything I Said, Yogi Berra