Help identifying my balance

A contractor from Baton Rouge says:
Need help to identify the balance number for the S390-29. Windows are standard not custom made. Here is my pic
User submitted photo of their channel balance stamp.
Profile picture of Mike
Mike from SWISCO responded:
Good Morning,

I cannot make out the stamp from your picture. It looks like 20 2 IT CMC - what do you think? (which would be wrong - the stamp should start with 28 if your channel length measures 29")

You can also look for the stamp on the channel balance on the other side of the window (it is possibly clearer).
A contractor from Baton Rouge says:
Channel length is 29" for sure and what the picture looks like to me is 28 2 IT CMC. But shouldnt the stamp number be 4 digits? If in deed it is stamped 28 2 what does that tell you I need to order?
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Paul from SWISCO responded:
If you are sure you have the S390 replacement channel balance you will need the S390-29 with the 2820 option. If you want us to help you with choosing the series, we will need to see photos of both the top and bottom balance attachments.
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