I don't think it's possible for vegans, but vegetarian I think it depends on what you will/can eat.
Many vegetarians/vegans get the bulk of their protein from beans, including soy. Beans aren't "acceptable" on primal/paleo, but lots of us make some exceptions. I use dairy, although I limit it. I believe that soy is not "allowed" unless it's fermented? But soy especially is not good for you. In small amounts, it's fine, but large doses is not healthy.
Soy is not at all primal, IMHO as it's only been farmed for about 5000 years....and a good part of that time it wasn't eaten, it was grown, then tilled into the soil, to replenish the soil so other crops would have the needed nutrients in the soil. I don't know how long we've been eating soy, but not very long! If you do have it, it should at least be fermented.
For vegetarians that are willing/able to eat eggs, fish and other animal sources of protein, I think they could do it. But if most or all of the protein comes from plants, I don't think it's going to be easy to get what you need.
Vegetable protein is not as bio-available as animal protein....and without soy, I can't see how eating only eggs for animal protein is going to give you enough of the right amino acids....unless you eat a boatload of eggs!