What’s the benefit of diagnosis?

One of my 12 year old twins displays some behaviours that I would associate with being on the spectrum ( not severe ). He is academically doing really well across all subjects however my main concerns are around limitations in social skills , particularly as he moves to high school in September. 

My dilemma is whether getting a diagnosis is of any benefit to my son or whether , conversely, it might re enforce any feelings he has of being different to peers and add to his isolation.? If academically he is doing well,what benefits would an assessment and diagnosis bring ? Trying to balance against numerous on line articles referring to teenage mental health issues is undiagnosed condition. 

Any advice really gratefully received. Thank you