I didn't know that Ireland still required silver to be assayed and marked. Based on all of those Peterson pipes with silver bands and no date letters or assayer's marks, I assumed they had not adopted that portion of English law after independence in 1922. (Ironically, Irish law is based almost entirely on English law, but that's a whole 'nother story.) Turns out all of those pipes (including the one in the OP) are nickel or some other white metal.
http://www.peterson.ie/t/hallmarking
http://www.peterson.ie/t/hallmarking
Hallmarking is not a legal requirement in many countries, but it is in Ireland. By Irish Law, the standard of most gold, silver and platinum articles must be tested (known as assaying) at the Assay Office of the Company of Goldsmiths at Dublin Castle.
Having established the legal standard of purity, the articles are stamped with a series of marks, known as Hallmarks.
All Peterson Silver Mounted Pipes carry three distinctive marks :
1.The Symbol Hibernia (Ireland) denoting the country of origin.
2. .925 is a new European standard mark denoting the high quality (purity) of the silver used.
3. The Date Letter Code for the year in which the silver was hallmarked and the pipe made.