Sash Balance stamp option

A sash balance broke in my window. There is a stamp on it: 2605DS. I found a sticker label on the window identifying it as series 437/438. There are also the codes [H-LC35-54x96] and [H-LC50*-52x76] printed on the label. I found what I think would work on your website, but I need the help of a professional since my stamp did not directly match with yours.

Also the window it supports weighs 32 lbs. I figure that is 16 lbs to each sash balance. If I understand this correctly, then I need the 27" Series 380 Channel Balance (option 2630). Would you agree?

Thank you so much, Paul! I realized by your response that I was ignorant that the window I described was called a "sash." I learned something new today and ordered a pair of 2660's for my window. Now the term "sash balance" makes sense also. Thanks!