My answer is ABSOLUTELY. I could have written a nearly indentical post about my two...last year. We did have our younger one tested, but only for admittance to a gifted charter school that required it. We had NO issues at all with him in school, and he was happy, happy, happy in every setting he had been in. He was bright, but not the kind of bright that has folks asking "How OLD is he?" One reason for that is because he was rarely around adults, preferring playing with buddies to the "academic" stuff that his brother clearly preferred from a very young age.
Imagine our surprise when he tested extremely close to his very PG brother (both are now DYS)...we became extremely thankful that we had done the testing when we started to see a completely different "flavor" of symptoms from him not too long after. We could use the "PG lens" and came up with possibly different diagnoses/solution sets than we might have otherwise. And we were so happy that we had done his testing when he was in a "happy place" and not in a crisis situation (our older son's first testing - the WPPSI - is what we refer to in our house as "the emergency test." We can now laugh at some of the things he pulled during that test, but it was NOT funny at the time!!).
If there's no reason NOT to test (money, anxiety on the part of the child you, etc.), I'd say go ahead and do it.
