Having looked at
https://github.com/siklon/cpuminer-gc3355 I don't think you can set the frequency's by the serial number but only by the device number ttyACM.. as these move around on reboot it is pretty useless ATM.
You can. Sandor changed this yesterday on his version. You have to update to Minera 0.1.9 to use this feature. I tested it yesterday and it's working.
But remember, you can't set frequencies on a single chip when you're using blades. This works only for grids.
On blades you have to use Serialnumber:Frequency without ChipID.
And remember... blades don't support auto tuning!