I thought G&B would be one of the easiest indicators to define but have found it to be the most difficult. They used quite a variety of shapes and styles and I see the same kind in a lot of different models. I know that jobbers, owners and restorers alike, would often use whatever is at hand, but G&B seems to be the worst at trying to determine any kind of consistency. This even applies when looking at old photos, sales literature and pumps that look "original".
I'll throw this theory on the wall and see if it sticks. When G&B came out with a new model they would also come out with a new indicator style. Not only the new model would have the new Indicator style but all other models in production would have the new indicators installed as soon as there existing inventory had depleted.
Now the challenge: Using the number under the indicators in the picture below, place them in order from oldest to newest. Example: ( 1,2,5,6,4,3)