Yeah... it looks like just the only difference is colour (brown vs. blue).
It's really crazy idea to name these models 10G, 10J, 105, 108 etc. - like a game with processors and colours. And it's easy to make a mistake and buy not what you want
I have checked specifications and I cannot find any difference. Both models have the same part number so both belong to notebooks with the same hardware configuration. So the difference can be colour only.
What I can see is NB550D-109 offered in more countries than NB550D-10G.
I've checked local and internet shops - strange thing - now, a month after they've started to sell NB550D, in my country (Poland) you can buy only 10J model (with C30) - only green! But the price changed from 1299 to 1199
And 10G model (blue with C50) disappeared - sold out!!!???