I'm sure it's the literal truth.

Never know when you need to seismically image some hostiles for scientific verification of threat elimination.

Probably was both. NASA got a COTS component for their seismologic experiment, saving some time/budget on R&D, and military got to have a grenade launcher tested on the Moon, providing data for whatever "future warfare" programs they were surely running back then.

I think these days we call this "synergy"?