The old green tip traditionally translates to the modern blue tip, but we always recommend weighing the sash just to be 100% sure.
If you are not able to remove the sash then the next best course of action would be to put a scale on the sill and gently lower the sash on top of it. It wont be 100% accurate, but it'll put us in the right direction.
It's unfortunate, however, the thing about these old windows is many of them were explicitly designed so that you cannot remove hardware like this. They were mass-produced and when they broke, the manufacturer likely intended for customers to buy an all new window, not just small replacement parts.
With that being said, we may still be able to offer a solution, as we do sell plenty of compatible parts. However, you will need to work around the window's limitations. Especially since you most likely won't be able to get the window removed.
