Flight review required?

I agree with Terry and Roger.

In

"§61.321 How do I obtain privileges to operate an additional category or class of light-sport aircraft?"

there is no reference to 61.313 which spells out the hourly requirements for, what I believe are, the initial Sport Pilot certificate. Since the Commercial Pilot certificate covers Sport Pilot privileges, there is no initial Sport Pilot certificate to acquire in this case.

Also, there is no regulation that I can find that says an applicant MUST be Acting PIC on either a Proficiency Check with an instructor or during a Practical Exam with an Examiner or Inspector.

If using it as a guide, the DPE Handbook strongly discourages a DPE from acting as a PIC during an exam. But I would assume than a Proficiency Check instructor would be more amenable to acting as PIC.