Can't say for sure. I think it's best to ask an electrician.
My question was more about the possible effect on sound quality rather than standard practices or code issues. An electrician would likely tell me the outlet will work fine without adding 10 awg wire jumpers. However, based on the significant improvements in SQ people report to result from relatively minor tweaks, I am curious whether anyone here has tried directly wiring both sides of a duplex outlet rather than relying on the internal plated jumpers to power the other half of the outlet, and whether they believe directly wiring both halves improves SQ?