I'd say take a wait and see approach. Perhaps get the testing done. But don't drive yourself silly with it.
Any decision you make with education at this age is reversible. Your son is young and it's not like any school situation at this age will cause him irreparable harm.
There's a lot of variation with kindergarten students today. The situation in MA is no different. Some kids enter K already reading; others barely know the alphabet. It really depends on far ahead your child is with the reading, writing, and math to other kids in the school or class OR how quickly your child will acquire these skills. With either scenario, you may not know what happens with your son until he is placed in a more academic setting and confronted with the material/curriculum. Even then, there are other aspects of education besides the academics that you might want to consider.
I just caution using the term and concept giftedness in MA because in my experience I encountered some public school teachers and schools who were completely hostile to it. You may find some public school teachers who are not so opposed to it. I hope you do for your sake.
