Do I really need left/right specific socks?

For racing, yes. The difference is subtle but real: anatomical socks have no excess material anywhere, which means no bunching, no wrinkles, and no pressure points inside the boot. In a race boot where the fit is precise to the millimeter, even a small fold in a universal-fit sock can become a distraction or a pain point over hours of training. If you're spending the money on race boots and race socks, the anatomical fit is part of the complete performance package.