GMPartsgiant, GMPartsdirect & RMSAuto are showing these available. I'm not sure if a local $tealership will have them in stock, but it's worth a shot.Fuzzcar
What a coinky-dink. My drivers side blade won't stay put and it's raining today; can't go to work until I fix it.
I thought the wiper arms were 22" for both sides. By chance do you know if these parts are still sold at the dealers?
10364940 Wiper arm, RH
10364941 Wiper arm, LH
12367275 Cap, arm finial—covers retaining nut (2 req’d)
11589150 Nut, arm retaining—same as B-body (2 req’d)
You could also try contacting Mike P @ Hamilton Chevy as well.