Could be. I think there might be some distinction in the terms. "Dark Jedi" is just a generic term for non-Sith Darksiders in most contexts if I recall.
Jedi
Sith
Dark Jedi (not a Sith)
Light Sith (not accepted by the Jedi)
Redeemed Sith (fallen back with the Sith after a period of rejection)
Redeemed Jedi (back with the order after a one night stand with the dark side)
Independant Sith (left the empire/sith to be their own competitor to it or become a bounty hunter, etc.)
Grey Jedi (Grey Paladins fall under this of course)
Could even go as far as provide extras for Grey Jedi, too. Since i'm sure it's possible to go against their teachings.
But this is all moot point, the OP still hasn't been answered, lol.
The ruling for any jedi/sith of any type is the same: You have to start out as a padawan/acolyte (unless given permission by the jedi/sith FLs), you can only have a max of two lightsaber forms (can't be an expert in either), and can only know a few beginner/basic force powers (can't be a master in any of them).
Gray Jedi don't have a set of "laws" like the Jedi. Grey Paladins do, but that is because they are a specific group and (according to wiki) usually added the Jedi from time to time. The Grey Paladins actually stayed at the Jedi Temple with the Jedi. (I've done research on them and the Light Sith when I was considering making a force sensitive faction)