Definitely NOT worth it!
Plus if they are not very good at doing it you could end up with swirls in your brand new paint.
You just need to apply a sealer to the car when you get it, and keep it topped up. The sealer is a kind of synthetic wax you can apply to new paint, and has no abrasives in it.
There is a lot of wax brand loyalty out there, but I think any of these are acceptable, mostly based on other people's recommendations:
Meguairs NXT Tech Wax 2.0 (liquid ie easier to apply than paste)
Autoglym Extras Gloss (red label)
Tutlewax Platinum Extra Gloss
Collinite 476S
I'll be using NXT on my new car the day it arrives.
You can get all of the first three from Halfords, from £9.99 for the turlewax to £16 for the Meguiars. A little cheaper off ebay. Make sure you apply sparingly with a using a proper applicator or CLEAN microfibre towel (ASDA have some coloured ones a real bargain).