Certainly be using the originals for reference though no doubts about that, thats right isnt it?
I just feel that the poly saving techniques of old would only get in the way when trying to create a fresh model if using the original mesh and adding detail.
You gotta keep in mind when unreal was made, the 2k4 invasion models were ports from the originals, just think of the tools they were using back then compared to the tools we have today. As an eg, put some q2 meshes next to their q4 counterparts, artistic style and differences aside you can see the difference the tools are making to todays pipelines![Stick Out Tongue :p :p](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
You gotta keep in mind when unreal was made, the 2k4 invasion models were ports from the originals, just think of the tools they were using back then compared to the tools we have today. As an eg, put some q2 meshes next to their q4 counterparts, artistic style and differences aside you can see the difference the tools are making to todays pipelines