Finally a fellow collector provided me with the info on the Spacequest set. He said this info came with the set. I think this finally answers the question about the silver content of the set.

Casino: Las Vegas Hilton Casino
City: Las Vegas, NV
Denomination: None
Design side: Space Quest Casino Boxed Set
Logo side: Space Quest Casino Logo
Edge: Smooth
Series: Limited Collector Edition
.999: Logo inner, .999 Fine Silver
Mint Mark: CC
Mint: Continental Coin Corporation
Mintage: 2500
Issued: January 1, 1998

Notes: Total silver weight ≈ 6.4 ozt.