Its more like we're giving them our older munitions and replacing them with new versions. They do have some purchasing authority and loan guarantees for certain things.
And that is typical with how we do things like that. We sell off our older equipment, and replace it with newer stuff.
However, even that is not quite accurate to what most people think. Most equipment (especially actual ordinance) has a shelf life. In general, most of it only lasts about 10-15 years. Then it needs to be either pulled out and inspected (a lengthy and expensive process), used (generally in training), or sold off. For most of the Soviet-Afghan War, we were not actually sending them the STINGER, but the REDEYE. That was the original version of the US MANPAD, and came out in 1962 and was manufactured until 1971. At that time it was replaced by the identical looking STINGER.
However, we still had a lot of REDEYE still sitting in bunkers. And how they operated was not as effective against jets, but it was effective against slower moving helicopters so that is what was sent to them. They only started to get the STINGER once the last of the REDEYE missiles in inventory were gone. The same missiles were sent to the Contras in Nicaragua. And even when they started to send STINGER, it was the older FIM-92 and FIM-92A, the main weapon had already moved in the US to the FIM-92B.
So in reality, it does nothing for the "Military-Industrial Complex", as the weapons and equipment sent is almost always our older stuff, that otherwise would simply have to be destroyed anyways. They just pull old stuff out of the ordinance bunkers and just inspect it and ship it off.
Quite often when I was at Fort Bliss, we would do life fire training with PATRIOT missiles. However, this training was never with the newer GEM or PAC-3 missiles. It was always with the older PAC-2 missiles that had spent the last decade in bunkers. And we knew it, as they actually only worked as expected about half the time. But when we did tests with newer ordinance it worked almost perfectly every time. They simply degrade in storage, and for the ones we used in training it was either "use them or they were going to get cooked".
And if you look at what is being sent to Ukraine, that becomes obvious. One of them is the M60 AVLB, a folding bridge that is carried and emplaced by an M60 tank hull. Now the actual equipment we use for that mission is now is the M1075 JABS, based on the M1 tank. However, we still have a lot of the old M60 AVLB in inventory, so that is a better option to send that instead of just scrapping them. We are also sending old export versions of the M1A2, which is about 3 generations behind what we are using or exporting now (M1A2 SEPv3 - also known as the M1A2C).
Nothing is being "made" for them, we are simply raiding our excess inventory and sending it over. Like the HIMARS, with the M31 rocket (circa 2005). The US expects to use the M31A2 and ER GMLRS if ever needed, but we still have a lot of the older M31 and M31A1 rockets in inventory.
