Yes it's true. You don't need a 990FX board to overclock. I have the Gigabyte GA-970A-UD3P and I've been running my FX-6300 at 4.5 GHz for many months now. It's just as stable as when I was running it at stock frequency.
The 990FX boards usually have a cleaner , more stable CPU power phase for extreme overclocks. I'm happy with 4.5 GHz so the 970 chipset was perfect for me. The 970 board I chose has the same power phase setup as most of the 990FX boards, that may be one reason I can get such a stable overclock.
I do agree that all the MSI 970 boards are junk. There are much better alternatives. Good luck!