When they stepped out of the recovery helicopter onto the deck of the U.S.S. Okinawa
the Apollo 15 crew were wearing blue jumpsuits with an embroidered mission patch attached.
The detail of these patches is clearly visible in the top row of photos on the right, taken
during the welcoming ceremony.
Later the same day, at a meal on the ship, the crew had changed into a different set of flight
suits and, as can be seen in the detailed images on the right, the patches on these suits
seem to have a different appearance. In reality, this appearance is just due to the
lighting conditions under which the photographs were taken.
The photographic evidence (with thanks to J.L. Pickering for providing high-res scans) shows that the patch worn by the Apollo 15 crew on their post-flight jump suits is almost certainly the regular AB Emblem mission patch.
Since this patch is not particularly rare it doesn't really qualify as a "crew patch" for the collector, although
it certainly earns the bare back vintage AB Emblem patch a place in any significant collection.
The 'official' Crew Patch for Apollo 15 has always been considered by collectors to be the one made by AB Emblem in which the "XV" is
embroidered in silver thread instead of black. This version was only supplied to NASA for use in official presentations
 and to the crew.
An even smaller number of patches were produced with gold thread instead of silver.
It seems likely that these were only given to the crew. Both the silver and gold thread versions of this patch are extremely rare.