29 Series 795 Channel Balance and shoes

Hello there. If the metal channel length is indeed 29", then it does look like you have an S795-29 Channel Balance. The T-Lock Shoe looks like the 1-1/4" open cam shoe 15-195B, sold separately. Your old stamp of 28-5 is from an outmoded rating system. To know what stamp to pick, weigh the window sash. You can use that exact weight to choose a new stamp option. 

Finally, check how the metal channel attaches to the top of the window track. If it uses a screw clip you should be good to go; if it's a hook that goes into a hole in the window track though, this is a custom item that we must provide via special order. Just let me know. 

Guide: Modifying the Series 795 Balance

Great. In that case get the 15-195B T-Lock Open Cam Shoe, and also the S795-29 Channel Balance. For a stamp option choose 29D, which indicates a balance that can support a window sash in the weight range of 23 through 28 pounds.