Peter Wright had a few different stampings through their history according to Anvils in America. The one I am most familiar with is as follows:
They had the name stamped, usually with "Patent" under the name. "Solid Wrought" was usually stamped in a circular pattern. After about 1910, the word "England" was stamped. Then the weight in the hundred weight system was stamped at about the waist level. There were usually characters stamped on the front of the feet as well.