Do all new iphones have ios7 already installed?

I'm thinking of buying an iPhone 5 sometime within the next month, however I'm not very fond of ios7 so if I buy a brand new iphone 5 will it come with ios7 already installed or will I have the choice whether to install it or not?

The iPhone 5 has to be upgraded to 7 the 5s and 5c come with 7 installed.

1st off, the iPhone 5 was discontinued when the 5c & 5s were announced. So getting one new is no longer an option.

If it was, it will come with whatever is the latest version of iOS at the time, in this case 7.0.3.