Well, the "tech" probably meant well, but his information is not correct.
It won't hurt to have an "n" wireless modem/router, but a 10 year old "g" wireless router will deliver 54 Mpbs, assuming that it is operating correctly.
Using an "n" wireless router won't make your 50 Mbps Internet connection go any faster, unless you are thinking of moving up to a 100 Mbps Internet connection. Then, the "n" router would make sense.
This is one of the few times I will disagree with Bob.. sorry!!
Real world file transfer over G wireless is no better than 25Mbps at its best.. and generally around 20Mbps.
G wireless at 54Mbps is half duplex.. that means you must at least halve the speed..
Same for 300Mbps N wireless.. you can never get better than 150Mbps because of the half duplex nature.
The OP was asking about Internet connection speed, so I answered assuming tha he was checking the connection speed....and he wanted to know if he could increase that speed.
My old Linksys 54G wireless router will deliver a bit over 50 Mbps when it is connected to the modem and I do a quick speed test on a 50 Mbps Internet connection.
A much newer Apple delivers a bit over 50 Mbps on a quick speed test....about the same as the old Linksys.
Transfering files from device to device over the local network would certainly go faster on the Apple, but I assumed that the original queston was about the Internet connection speed.
I still think you need N wireless to saturate a 50Mbps internet link..
But to the OP test it..
If you download a file via wireless from the Internet and 50Mbps on G wireless you are my hero forever..
If you download a file via ethernet on an old Linksys eg WRT54G it will not do any better than G wireless.. they are simply not up to the WAN to LAN throughput.
So test carefully.. a 50Mbps link should deliver 50Mbps under ideal conditions. usually an FTP source provided by the ISP. If you get poorer speed than that.. replace it with N wireless router.. with WAN to LAN throughput that is at least 300Mbps.