Is a disc that has a Prototype stamp, but no PDGA Approved stamp, on it approved for PDGA play assuming the mold was later approved?
For example the Discraft Ace Race discs.
Yes, all are approved when the PDGA says they are good.
"PDGA APPROVED" on a disc doesn't mean much. Some manufactures have been caught putting that on a disc before they even sent it to PDGA. Just check the official list. PDGA Approved Discs PDF