- New in box stock radio from the manufacturer
CB radio shipped from the manufacturer are produced and tested using their equipment and are adjusted so that they meet or exceed all federal requirements for CB transmitters - (less that 4 watts output, no harmful interference, etc.).
So from the manufacturer your CB radio is set up to work according to all FCC rules and requirements.
So if you want your CB radio to perform as intended by the people that designed and produced it then NO you do not need a "peak and tune".
Peaking a radio generally means adjusting certain items inside the radio so the radio puts out more power (watts) and has more modulation (sounds louder on the air to other people listening).
Having your radio peaked means it may be able to transmit slightly further than it would stock. Most radios come with their modulation levels set below 100% and power set slightly below 4 watts (legal maximum) so making these adjustments may allow you to be heard over a longer distance.
However - these modifications also may make your radio technically illegal (if it no longer meets FCC requirements) although there is very little risk of getting in trouble. The modifications if not done correctly can damage your radio and even if done correctly may shorten the lifespan of your radio slightly.
Now tuning can go along with peaking and mean "tuning" your radio for peak performance OR it can also mean what we call an "alignment" which includes checking and adjusting voltages, frequencies, etc. Most shops don't bother doing this when they "peak and tune" your radio, they simply are turning up power and modulation. Out of the box your radio really shouldn't need an alignment anyway.