As someone who works with the government a fair bit, this kind of forward thinking is extremely unlikely to be the case. This is the kind of government competence that only exists in the most wild conspiracy theories.

The idea that it was made by some long defunct subcontractor and nobody knows what happened to their blueprints and production notes is far more likely. Also, even if you had the blueprints you still need to be able to make the tooling, which is at least half of this project.

That said, if some contractor does come through with this and does a good job (on time, on budget, parts work, etc...) they could likely find plenty of other programs with similar needs. In some cases the original contractor does still exist, but they're asking way too much money to reconstitute an old production line so a scrappy startup like this could prove themselves valuable.