Thank you for submitting your photos.
The balance stamp option you require is 2840. However, we will need to see images of the balance attachments, and the length of the channel, in order to determine the balance series.
Is it necessary to have the exact item or could you recommend an alternative that will work with my series 380? I am replacing the balances on all windows.
The 18-036 Top Guide should work with your application, however you will have to drill the top hole.