Question about pvp gear scaling?

I am new to the pvp gear scaling and am not sure how it works. I am looking at the algari gear and it says it scales to 606. Then another one in the auction house says the same thing but it’s item level is higher at 610 for the same item. Will the 610 one be better or will they both be at 606 in pvp?

Another question would getting a random green that is already item level 657 be better than both of those pvp item?