Can't Match Balance

A home owner from San Jose, CA says:

I looked through your balance images, but could not find an exact match. The attached photos will hopefully let you figure it out.

These are from two windows weighing 34 pounds each (four springs total). I noticed that the numbers on the side are different.

Channel Width: 1/2"
Channel Length: 32"

Codes on balance:
31 9 HS
31 9 38#
User submitted photos of a window balance.
Profile picture of Tom
Tom from SWISCO responded:
Hey, thanks for posting. I've narrowed this down to two possible channel balance Series: either our Series 351 or our Series 390 balances.

Now, as you can see, there is only one difference between these two Series, and that is their bottom shoe. The Series 351 uses the 15-002 while the Series 390 uses the 15-001. I can't quite tell what you have based on your pictures, though. Please carefully compare their dimensions to your own hardware and see which is a better match.
Comparison of <a href='Channel-Balance-Shoe/pd/Replacement-Sash-Support-Channel-Balance-Shoes/15-001'>15-001</a> & 15-002
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