Standard mark certifying the fineness of metal: harp
Twenty letters of the alphabet of different fonts together with the shape of the escutcheon identify the year in which the piece was verified by the assay office.
Peterson buys sterling silver bands annually by the thousands and sends them to the essayers office in Dublin to be essayed and hall marked. Upon receipt of the silver bands, K&P would distribute them to the various finishing stations where they may be dumped on top of older dated silver bands. Thus due to this inversion layer of bands, it may be two or three years before the older bands are used, meaning the pipe itself is two or three years newer
than the dated band. There is no absolute way of telling these pipes from ones that use the year band in which the pipe was made.