It is outrageous and you have been misinformed by whatever tech looked at the system. It wasn't a very good technician if he couldnt figure what he was looking at. Dell normally uses very standard Wifi components. So much so that they are often easy to install OS's such as Linux that don't have open source driver support.
Did he buy this new from Dell? If so (or, even if not), look up the "service tag" on Dell's support site and it will tell you exactly
what is in the computer. This is a very easy thing to do via:http://www.dell.com/support/troubleshooting/us/en/19/Index?c=us&s=dhs&cs=19&l=en&t=system
Or, post the service tag on here and someone can look it up for you.