I would say that it is good to have an opinion or point of view on the final manufacturing detail, BUT different manufacturers will have different equipment, different processes, different capabilities, different crafts people, and this will all lead to having different preferences for how they all might want to make the same piece. Some differences may be subtle, others may be drastic, but in general when working with a manufacturer, you need to be able to work with them to help them understand how and why you might want to do something one way, and also be able to understand their core competencies and strengths to understand how you might leverage them to execute your idea or make something better or different. The greatest asset you can have is the ability to learn and adapt and be willing to teach and communicate. As far as the deliverables go, being clear about design intent of your prototypes and models is important, they may have ideas or capabilities that you were unaware of that may help execute on your intent better than your original idea, but you may have been unaware of. The “why” is generally more important than the “how”, they are almost always several ways to do or make one thing. That being said, coming to the table with a few ideas on the “how” is almost always a good idea. I guess another big thing to consider is that in most in-depth partnerships with a manufacturer, the design intent model or prototype and initial drawings should feel more like the middle of the conversation than the end.