Shield boss dating / typology

[M. Demetrius]

That would be interesting. I'm getting curious about how/when the trends went from the "barleycorn" of the old repbulic to round and squareish boss flanges in later times. I wonder what the percentage of those two would by expected. Seems like the default is round, usually with 4 rivets. I couldn't begin to know where to look for the data. My history books are not nearly specific enough for things like that. I'd love to be kept posted on the progress, though.