Replacement Window Balances

I need to find a replacement part for two window balances. The original items are probably from when my house was built in 1993. It appears that the window sits on the white nylon(?) bottom pieces of the window balance and uses friction to hold the window in place when it is opened.

Window Frame: There is a top clip on each of the window channels. The hook on the balance only has one hole that it could hook into, but that hole is above the top of the window when the window is fully shut. There is one small hole at the bottom of the window channel.

Window Balance: The metal part of the balance is 29". The width is 5/8 of an inch. There is a manufactures stamp "28 3 Caldwell BM." Has brown tips on the top. Has white nylon(?) pieces on the bottom. There is some rust and some degradation of the plastic pieces.

Window: Window is Jordan brand, aluminum frame, with double pane glass, 30" H x 34" W, and weighs 18.2 pounds.