Some information below that I have saved:
The 307 is an original Patent bent billiard-shape, shown in the 1896 catalog as shape 9. It has retained its original shape number in the De Luxe version, but was issued in the 1937 catalog as the 307 (2nd quality) / 357 (3rd quality). Since then, it has also appeared as the 9S and 9B (De Luxe), Dunmore System 78 (1978-1983), and the Classic Range 9BC (1940s-1950s) / XL90 (1980s-Present). The 9B dating from the 1940s-1960s (the De Luxe System with a tapered rather than saddle bit) is rarely seen on the estate market. There have been changes in the shape since the 1960s, all toward less “cheeking,” making earlier versions, when available, preferable to those wishing to get back to the first, classic iteration of the shape.
The pipe has a nickel band stamped with K&P next to PETERSON over the hallmarks Shamrock/Wolfhound/Tower, all on the left side. Marked PETERSON'S over SYSTEM over STANDARD on the left side of the shank and MADE IN IRELAND encircled next to 307 on the right side of the shank.
PETERSON PIPE DATING
1875 ~ 1915 The Patent Era no country of manufacture stamping, COM
1915 ~ 1949 The Pre Republic Era
1915
~ 1922 “Made in Ireland” in block letters with forked
1923
~ 1937 “Irish Free State” in block letters in 1 or 2 lines
1938
~ 1942 “Made in Eire” in small circular letters
1939 ~ 1945 WWII years there was a shortage of briar so few briar pipes made
1942
~ 1946 “Made in Ireland” in small circular letters
1947 ~ 1949 “Made in Ireland” in block letters with standard
1950 ~ The Republic Era
1950 ~ “Made in the Republic of Ireland” in block letters in 2 or 3 lines,