How to identify the correct Anderson double hung sash balance?

A home owner from Vermont says:
I'm looking to purchase replacement sash balance assemblies for my Anderson non tilt double hung window. The date code is 2-99 clear window measurements are follows:
Lower window; 36 3/8" wide 13 15/16" tall
Upper window; Same dimensions.
Is this enough information or will I need to disassemble the window to access the part # on the balance assembly?
Thank you,
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Tom from SWISCO responded:

Hi, Glen. In my experience, going by sash size alone is often unreliable. I find it only works about 50% of the time. For that reason I always ask to see a picture of the stamps printed on the balance box itself, which will require removing the sash and jamb. You may find the video below to be of some use.

How to replace an Andersen Window Balance
How to replace an Andersen Window Balance
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