Well, the auction says it was from his estate. It could all have been prearranged, or memorabilia was packaged, or even sold some time ago by the family. But what is interesting is that the claim in the ad is probably true. This knife was likely a NASA knife, later carried in Vietnam, and probably Laos and Cambodia... hence the (model 15?) sheath.

Most of the things we regarded as meaningful during our life will be just another artifact to our heirs. I just dumped a load of my step-dad's history... except we kept the personal pictures of the Bikini Atoll underwater nuke test he took from 8-miles away.