As far as I understand you still have to buy US, and need approval if you cannot source domestically.

All our military work still uses US electronics shops and machine shops.

The window has shifted as to what constitutes “us made” though. For most things “US assembled” is the norm, and when you get out into things like office supplies, vehicles, and construction materials it’s often far from true domestic manufacturing. For strategic military stuff it’s better, but often at the cost of using 1990s tech because we don’t make the newer stuff here. (It also has the effect of making things more repairable, but that argument gets weaker and weaker as time goes on)

At this point I think in practice it’s a preference for US manufacturers but a long way from robust enough to establish domestic supply chains.

Also -a lot- of military purchases are local, discretionary on a credit card, and there is no oversight on the origin there- it’s whatever they need from office max or the hardware store.