The stamped marking of "5d" on the guard (before the possible "2") could represent the cost in ducats.
For instance, a pair of razors could be purchased for 5d in 1588. In 1620, a leather satchel was worth 8d. See A History of Agriculture and Prices in England
(1259-1792) by James Edwin Thorold Rogers.
t.y. elle... I might be letting my imagination run away with me but looking very closely at it the 2d looks superficial as compared to the stamped or incised markings. would something like that happen on a trade item?