Replacement Cleat for Double Hung Windows

Hi, looking for replacement 'cleats' if that's the right word for them...this part anchors one end of a spring and, no surprise, the plastic eventually snapped under the tension. The measurements of the cleat are 2 + 7/16 (L) x 9/16 (H, at tallest) x ½ (W). Pulled from the channel of a BiltBest Aluminum Clad double hung window, circa 2008. Ideally, there's a compatible metal part that would be available...

I'd also appreciate at least knowing the name of the part that I'd call a pin that is featured in one of two 'pin' photos and is missing in the second...need to replace that too...