28D and 22F stamped balances

Thanks for posting. You should never replace a window if the balances are the only problem. Windows can cost thousands of dollars, while balances are inexpensive and easy to replace. 

We do recommend replacing them both at once, yes. I think you have either a Series 380 or Series 385 channel balance, depending on the size of the shoe. This applies to both types you show. You'll have to measure your shoe and refer to the measurements on our site to confirm the best match.