But the damage was done. Scott and Irwin transferred to other NASA centers before retiring while Worden briefly returned to Air Force active duty.
To prevent similar incidents on future flights, NASA drafted rules about what astronauts could take into space and stipulated that the contents of Personal Preference Kits (PPKs) couldn't be publicized until they retired from the corps. Astronauts were also required to sign an agreement saying they wouldn't give away flown memorabilia as either a gift or donations. Sale of memorabilia for whatever purpose was strictly prohibited.
HOWSTUFFWORKS: How the Apollo Spacecraft Worked
The Apollo 15 covers didn't resurface until 1983 when the U.S. Postal Service announced that 260,000 covers would fly on STS-8. Worden, to whom the similarities between his confiscated covers and those now sanctioned to fly on the shuttle, sued the government for the return of his crew's 298 covers. The crew won and got their covers back in an out of court settlement.
The incident, strangely, was equally damaging for Jack Swigert's career. During the congressional investigation into the Apollo 15 stamp incident, it came out that Swigert had taken a significant number of covers on his own mission, Apollo 13, then sold them for profit. When asked about this incident he refused (in some apparently very strong language) to say anything. This move didn't exactly endear Swigert to then head of the astronaut office Deke Slayton. Slayton pulled Swigert permanently out of the flight rotation.