Ah. Then you're all set. Yeah, it does have a few visible differences. It's has a 3-bolt cam gear versus the Gen 4's single bolt. This is why you use the cam gear that has the Gen 4 timing triggers but Gen 3's cam bolt pattern.
Yup- let it ride. Don't beat on it and keep clean oil in it and you could double its current mileage.
Document, document, document! If you ever have any doubts about something, having pics to refer to can bring peace of mind. Of course, ask others first if you're unsure of something!