I didn't look to see whether any of the shirts indicated whether they were made in Italy or the US or elsewhere.
The heavier weight flannel shirts (I have a tattersall) were made in Italy and were quite expensive. They're outstanding shirts, similar in quality to the Oxxford and Kiton flannels. The USA made dress shirts that I saw at Sulka in the '80s were far more pedestrian in terms of cloth quality, buttons, etc. By the early '00s, the salesmen at the Park Avenue store next to Dunhill (at 56th) complained about lack of business. Prices were quite high. $1600-$1700 retail for a navy blazer. Shoes were stocked one year and abandoned soon after.Believe it or not, Sulka had a mass mailer for a $125 cotton t-shirt made in Italy.