More information: the set is actually six in total:

Apollo 11

Challenger

America in Space

Mariner 6

Surveyor 1

Lunar Roving Vehicle
The first four sold on ebay today.
The same set was also made for Trump Castle. However, neither set ever went into play on the casino floor. Strikes were actually made and delivered to the casino but were later returned and destroyed. It is likely the four sold today are sample tokens.