Need help determing if this is a Series 380 or 385

I'm looking for replacement channel block and tackle window balances (2), but I'm confounded if I need the 380 or 385 series. This is for a vinyl sash bathroom window where the cord has been shredded in the pulley mechanism. The metal channel is 13 inches, and the top guide and bottom shoe have wings. The only stamp reads "12 3 GW CMC 7". I can find no manufacturer information or markings. There is no stamp for the weight range (unless that's what the 7 indicates on the stamp), but the window weight is approx 7.5 lbs, so option 1220 should be correct. I'm unable to share photos of the balances installed, but have attached several photos from different angles of the removed balances. Additional photos available on request.

Thank you for your response Emily. You've included a photo that shows the correct way to measure the shoe width (this wasn't obvious from the previous content I viewed). I've done this, and while close to 1 inch, it's obvious it's a bit longer -- though perhaps not as much as 3/32 longer. Still, it'll be easier to trim to fit by sanding if it's too long, so I'll go with the 385. I appreciate your time!