Frame and other black steel parts - gloss. Some might say satin its not really though. I have have had/still have many NOS in packet black painted steel suzuki parts from that era and its obvious that suzuki intended it to be gloss, its just that the paint was done straight onto bare metal, and done to a price and it is very thin and there is no real depth to it. When you have NOS parts or find areas of original paint on the frame that have been covered and not exposed you will see that it was a gloss and not satin, its just that it does not quite have the depth of a modern day 2 pack gloss finish, which is done over etch primer and high build undercoats.
Engine - satin
Triple clamps - champagne gold metallic, satin
All other steel parts that were not black were normally champagne gold too
Hubs/brakes - satin
Champagne gold 08C is the same as suzuki automotive code 35P. Du Pont/Spies Hecker #90595
Theres loads of discussion on powder coat vs paint on here already so i suggest you have a look whats been said many times before. I think you are thinking along the right way though.