I have never seen a prohibition against copying a part, as long as the OEM logos are not used. Technically speaking, the windscreen design is not patented, copyrighted, or trademarked, so copying it is not a problem. That is why Safelight, Pilkington, Fuyao, and others are able to sell replacement windscreens. They will buy an OEM part and design tooling to make the same thing. When the contracts were limited to the parts themselves we were able to use the tooling that we designed and built to the drawings instead of a sample, so it cut out a big step in producing AGR parts. Now the contracts are to design and build a tool, then to use it to make the parts. Since they are paying directly for the design and construction of the tool they own it, and that is why we can't use it for anything but their parts.
We used to see a lot of that, mainly from the FNPs who called it a "cost-down". Now, with much more aggressive quoting, it has mainly gone away. We do still see it on some occasions, when a part is exceptionally complex and we know there will be a steep learning curve, but then the cost-down is limited to the first year or two.
Sky NA 2007 Midnight Blue
Sky RL 2008 Carbon Flash - Naked