Milgard 26 GW CMC

This looks like either a Series 380 as you are suggesting, or perhaps the Series 385. The only difference between these two balances is the size of the bottom nylon shoe, so compare both with your old hardware to see what matches best. 

You indicate in writing that you need balances stamped 26-4 and 26-5, which would indicate you need 27" long balances with stamp options of 2640 and 2650. Your photos instead indicate you need 33" balances with a stamp option of 3240. Let me know if you have any other questions.