4095 spring

I'm afraid I don't recognize that stamp. It's also very hard to read in your photos.

In these situations I usually cut to the chase and weigh the sash. You can do so with any common bathroom scale, but just make sure you get the weight down to the ounce. If you tell me that weight, and tell me how many springs per side you use, I can suggest a weight option for you.

I also think right now it would be best to get a photo of the pivot shoe, just to be safe.