Channel sash balance BSI NE

I want to buy a pair of sash balances for a single hung window. I would like to buy the entire assembly rather than re-build from parts. The original is manufactured by BSI and the part number is 2830. (there is also an "NE" stamped by the "BSI"). The metal channel length is 29" long. Our home was built in 1986, if that helps. The channel width is 1/2" From your web site, the top guide appears to be 19-005, and the shoe appears to be either 15-001 or 15-002 (my guess is -001, based on dimensions). However, I don't want to get it wrong. I am attaching photos of the top and shoe. Can you tell me what to order based on the manufacturer?