You're right, but the failure to deny it is conspicuous.
Nothing to lose except the opportunity to keep this off the OP's driving record by taking traffic school. Also, CHP officers don't fail to appear, and a failure to appear would more likely result in continuance than dismissal.
Unless you deny that you were doing 77, you were speeding regardless of whether VC 22349(b) is used or the law for exceeding the posted speed limit is used.

