I have encountered a number of instances with HB steins where there has been an engraving on the stein by a previous owner that often has a date. In many instances the engraving coincides with when the stein was made and is a reliable means to date the stein. In some cases however, the engravings on the steins are much later than the date when the stein was produced and first saw usage. What the date on an engraving can definitely tell you is the latest possible age of a stein. Below is an example of a stein that I just purchased that has an engraving on the inside of the lid, that is far later than the date when the stein was produced. The makers mark on the stein, which is partially engraved over, indicates that the stein was made by W. Wild, whom from my research made HB steins in the 1880's. The crude way that the HB is etched is also indicative of an HB stein from the 1880's and not something that was done in the late 1890's. The engraving on the stein bears the name P.Kröber E.Friedrich and the date Easter 1898. It is likely that this stein was a gift, or perhaps passed down to the person whose name is engraved, by the original owner of the stein.