There is no difference in the cables except in terms of quality.
A good quality SATA cable will support SATA III transfer speeds just fine.
"I dont know if I have Sata 2 or Sata 3 (cables)"
You don't have either. They are just SATA cables. It's the manufacturer's which have caused all this misunderstanding. They call some of their cables "SATA III" just so they can charge more for them. It's a con trick.
Just buy good quality cables.