No. You get whatever your role in the team or unit calls for, i.e. sentry, grenadier, AT4, M-4, M-4 with M203 launcher, shotgun....
And it is randomly assigned to you. Sometimes you'll get a crappy one, sometimes you get a less crappy one. If you are Special Operations you can usually outfit your rifle in different variations such as lights and things. There will be gear that you are required to have in a certain place, i.e. laser. Also you may get to choose between different optics, i.e. EOTech or ACOG.
If you are in a regular outfit then you usually get what they give you.
