Re: N68C-GS FX and FX chips
Yes, the FX-6100 is supported and on the list and it is unlocked. Not sure if you'll get full support as the FX processors are only officially supported on the 900Series chipsets. You have a 600 series chipset, so you may be limited on some features.
With that being said I'm sure it will perform well. Just take it easy on OC as bulldozers use a lot of power and that MB may have issues and throttle your cpu. Typically you want 8+2 phase power for the 8-core bulldozers and I'm sure the 6-cores need a lot as well.
Just check the BIOS version on the motherboard as it needs to support bullldozer or it won't post anything.
The 125-watt processors won't work as they will be blocked in the BIOS. Plus that board may not handle all that power. Be very careful if you OC that 6100. In fact I'd probably try to under volt it so it uses less power. You can probably OC at the same time. My 8120 was was undervolted 1.0v at stock speeds. (1.45v & 3.2GHz was stock) and I got all cores at full turbo of 4GHz and 1.25v. Just watch your temperatures.
ps. the cpu numbers are different because the boxed cpu get a code with BX or similar on the end.
ASRock Z68 Extreme3 Gen3 i7 2600K 8GB (2 x 4GB) G.Skill 1333 CL9 MSI HD 7750 Corsair TX850 80Plus
GigaByte A75-UD4H AMD A*-3870K 8GB (2X4GB) G.Skill 1866 CL8 On-Chip 6550D Antec EA-450 80Plus Platinum