Nope, I wouldn't. I don't even think that medical doctors should be told what a first opinion was if you're going to them for a second opinion.
Would you withhold previous blood work, MRIs, etc. as well? To me that seems like the equivalent of withholding IQ testing. My perspective might be different if we were talking about whether or not to give the results to the school, but in this situation it is a specialist in gifted 2e kids. Anyone good in this category often sees kids who have been badly tested or misdiagnosed first and they know how to deal with that.
