I realize this has been modified but i doubt the bottom plate would be changed. I looked at my CE-3 and its green label japan, but you can clearly read green label Taiwan on this one.
Yes, looks original to me. I have a green label MIT CE-3 myself. The knobs with white tops usually mean that it is made in Taiwan. The japan models usually have all black knobs.
I also have an MIT CE-3, and I run it through my effects loop. It sounds good to me stock. To me modding a perfectly good sounding pedal is a waste of money (I know that others will disagree with me on this). The only Boss chorus I would want modded is the CH-1.
I would normally not mod a pedal that sounds good as-is, unless there were some good improvements made that took the pedal to a new level. For example, I have a modded CE2 which has a vibrato sound now. Not the vibrato sound that the VB2 creates, but a true vibrato like on a vintage amp.