My manual says 62 mph down at 39 mph. If your wing did not deploy, you weren't at 65 mph, you weren't even at 62 mph for any period. I'd say explain that you might have accelerated faster than the pack but speeding you were not and that if you were, the wing of the vehicle would have simply deployed. I'd also throw in that you realize the unique look of the vehicle combined with the acceleration may have caused the appearance that you were in-fact speeding; but you were not. In any event realize that being polite and referring to the judge as "your honor" will get you far. For example, "I will accept any judgment doled out by the court and your honor, however, my plea is not guilty because I was not speeding; if I was infact speeding, I would not contest this ticket; I'd be upset I was caught but I would pay for the infraction, I would not waste the court or your honors time today". It also helps if you don't have any major prior moving violations and be sincere, which should be easy; because you were not speeding.

Oh yeah be sure to include that the officer in question was simply just doing his job and you respectfully disagree with his observation; and if it was you. You would of probably thought the same.