I'm a little confused on the statements and questions here.

As for the icons, from the first System/Finder .97 to 6.08 were the same icons to keep things simple, though things were added in System/Finder 4.0. System 7 inherited the icons System 6 had and then had "3D icons" in OS8. OS9 inherited 3D icons from OS8. There are some versions of System 7 with 3D icons, but those icons were taken from OS8 and hacked into System 7.

As for Contextual Menus - if  you mean menus within menus, thats a System 7 feature and accessible from the Control Panel, I forget which one.