Although in the past, we didn't need foreign tech to install in our weapons, we could make anything we needed. It was the opposite, we needed to sell our tech to potential enemies so they could install it in theirs. Why? Because it was profitable.
Capitalism knows no country, serves no ideology. Its all about money.

Remember when Mauser thoroughly updated and perfected the bolt action for the military rifle? Not only did they sell every potential enemy nation in Europe the mechanism, they also sold off the manufacturing licensing rights so other countries could learn to mass produce Mauser bolt actions on their own.

Closer to home, one firm I worked for sold a fully configured image processing system (dedicated hardware and software) to the Red Chinese, thereby jump-starting the image processing/remote sensing industry and technology in that country.

Oh sure, they didn't get any real secrets, everything they received was available in other countries, either because we had already sold it to our allies, or because they or the USSR had developed it on their own. But selling them a fully functional system with data, manuals, installation services and training, not to mention service, maintenance and update contracts, allowed them to immediately come up to full capability in a vital intelligence and reconaissance field without slowly and laboriously building up the human and technological infrastructure from scratch. I estimate we saved them ten years of development and engineering time.

Even so, much of the tech we sold them was considered "sensitive" in those days, both hardware and software, so it was necessary to get waivers from the government to sell the Chicoms a lot of this stuff. That proved no problem, we lobbied the Reagan administration and they were very cooperative. Everything was strictly legal, and aboveboard, and I'm sure it did wonders for our balance of trade figures. Still, it was essential to get those waivers, dot the i's and cross the t's, if for no other reason than "to keep the Democrats in Congress from making political hay out of it". Also, we wanted to sell it to them before the French could sell them their IP tech. With their SPOT system, they were our big competitors.

So the Red Chinese didn't get our latest hardware platforms, or some of our newest classified code and intelligence IP algorithms. But they did get a fully functional, fully factory-supported system they could reverse-engineer, quickly bring up to date and even improve. After all. There is no denying they are a clever people. They paid a premium price, but they saved themselves the time and expense of all the mistakes we had made devloping that technology.

Wasn't it Mao who once said "The last capitalist will hang from a rope sold in his own store."