Powell's somewhat opaque account does not square with DPD'er Joe Smith's, or Weitzman's.
Smith said he approached the Secret Service-badge flasher in the GK area, who looked a little grimy, and then was shown the ID.
Powell also said he would have said, "I’m a special agent with military intelligence. And show my credentials."
Additionally, Powell's ID did not looked like Secret Service ID.
AI:
Identification cards issued to the U.S. Army's 112th Military Intelligence Group in 1963 did not look like U.S. Secret Service credentials.
Standard Military
Design: Personnel from the 112th Military Intelligence Group carried standard Department of Defense or U.S. Army identification cards (such as Armed Forces identification or Geneva Conventions cards), which featured distinct military branch markings, serial numbers, and service insignia. [1]
Secret Service Credentials: Secret Service credentials utilized a completely different layout, seal, and departmental identification specific to the Treasury Department (under which the Secret Service operated at the time), frequently accompanied by a specific metal badge rather than a standard military card layout.
Both Weitzman and Smith said they saw Secret Service ID, not another ID. Neither said the man they approached ID'ed himself as "Powell," or said he was from military intelligence, and neither saw the man holding a camera.
I put low odds that both Weitzman and Smith approached Powell, and both mis-read the ID they were shown, and then both failed to note Powell was holding a camera.

