Arms will be 3/36. You are past. Simple as that. 6/60 does not include suspension, covers powetrain only (engine/transmission/diff) TSB are not a warranty item, as stated they are a guide for diagnosis / repair only.
That all typed, your dealer can petition GM to cover the repair (full or partial) as a exception.
Been there, done that on my other GM's
9.5 RPM (Red Passion Metallic) Sport /Premium
"Experience is what you get when you didn't get what you wanted."- unknown
All it takes is a little imagination, some mechanical ability, and neighbors who mind their own business. -red green