Sort of. The logic is a little silly, but I'll do my best to explain.
Most channel balance stamps are made up of four digits, like yours. The second two digits are sequential (10, 20, 30, 40, etc.) and we use them to determine the calibration of the spring. 1620 in your case is the second strength grade for your size and indicates that two balances can carry a sash weighing 8 through 20 pounds. The first grade is 10, which indicates 5 through 8 pounds, and the third grade is 30, which indicates 12 through 14 pounds.
This exact weight range isn't something you can determine just by looking at the stamp, so don't worry. That's information that our company has access to, and we do provide it on our site for each balance size.
But what does the "16" mean? That indicates the height of the visible glass. This is a little frustrating to me since many customers (rightly) assume that it indicates the actual length of the balance. Instead, it's always 1" less than the actual length of the balance.
In other words, we can look at your stamp and know that it's 17" long since the stamp starts with "16." I know it's confusing, but that's just how they do it. Hopefully my explanation makes sense!
