Your other thread says that others can "barely hear you," while this says simply "problems with call quality." Assuming your issue is that you're quiet or just hard to hear in general when talking on the phone, your radios most likely aren't at fault. Besides, it should take no more than a minute to flash them (aside from the CDMA radio write time), so if you want to try it, why not go ahead and do so? Anyway, it's very possible that you have some sort of debris (dust, lint, etc.) stuck in the microphone of your Nexus, even if it isn't visible to the naked eye. Using a compressed air duster with the straw attached might help ensure that the microphone itself is unobstructed.
Keep in mind that radios are preserved through wipes and flashes (except for full OTA update packages), and so they won't be changed unless you flash them individually -- though it seems you know this already. It can't hurt to try flashing them again, but the most common causes of being hard for others to hear are physical issues with your microphone or an area with substantially poor signal.