Although recently there has been some speculation that the Nokia C Series doesn’t exist, it appears that a Nokia device carrying the label RM-612 has been cleared by the FCC, a mobile phone which sports quad-band GSM, tri-band WCDMA, WiFi 802.11b/g and Bluetooth reports an article over on the Nokia blog.
On checking with the Nokia website they also note separate documentation which connects this codename with its commercial name, that name being the Nokia C6-00, and thus the rumour is the RM-612 which has cleared the FCC is in fact the Nokia C6.
The only image of said device at the FCC is an outline sporting the FCC label and no other information is available at this time, and of course there’s no official conformation so threat as rumour for now.
They do say that based on other rumour about the Nokia C Series handsets their guess would be that the Nokia C6 will be a touch screen device in the lower end segment and running Symbian^1.