Let's just copy the RD180. I doubt it has any patent ecumberances.
They've already licensed the damn thing for domestic production from the beginning and had a good decade where they could have set up their own factory and had the Russians come in and willingly ensure they are being produced correctly and fix any detail not conveyed properly on the plans. In fact, I believe that the RD-180 is more of a work-for-hire specifically commissioned for Lockheed's requirements.
Now everything is sour and steps to remedy it look political, rather than just a way of giving jobs for American blue collar labour, which is how it would have appeared before.
The RD-180 is a good engine that provides staged combustion performance and efficiency at similar cost to American gas generator cycle engines. The only problems with it is that it was really hard to design, which is irrelevant when you have the plans anyway. It would be a shame for NIH syndrome to screw up America's capability to launch satellites.