Your stamp number correlates to a 27 inch channel balance, stamp option 2640, but if you think you need a series 380 balance I would like you to take a look at something for me.
The series 380 and series 385 balances are the same except the shoes.
Comparison of the S378, S380 and S385 balance shoes.
The series 385 balance has the 15-004 shoe which is slightly larger from front to back, as illustrated.
If you measure your shoe as it is pictured here, you should be able to determine which one you need.
Please let me know if you have other questions.
