are there any physical differences between the two heads? Or any way of telling one from the other by looking at them?

 

right off my head, the only thing I can think that would be different between the two would be year of the head stamped between the 4 and 3 primaries of the exhaust manifold. 2nd gen have grey plugs where 1st gen have kinda whitish plugs. both have different font size writings on the valve cover. there's some more I know I forgot.

 

i've been looking at a bunch of pics of the two of them, and on all i've seen the sirI has "honda motor co." on the exhaust side of the valve cover and the sirII just says honda. maybe that's one way. thanks for the help.