Ninja 650 camshaft switch

I must vent, but don't belong to any Ninja groups, so I'm posting here.

I'm adjusting the valves in my son's 650 Ninja (two cylinder) in which the camshafts must be removed to get to the shims.  He bought the bike used two years ago and ran it hard and fast since.  It ran good but was due for a valve clearance check mileage wise.  I got to them yesterday; one intake was in spec, all others were tight.

Upon removing the cams, I noticed that the intact and exhaust cams had been switched by whoever worked on it last.  I looked at the throttle body, headers, and cams two times to make sure that it was not I who was turned around.  A quick Internet search tells me that the cams are not interchangeable.

Now, even if someone tells me here that they are interchangeable, I'm will reinstall them in their proper places and recheck the clearances.  Who knows?  Maybe I'll get lucky and some valves are in spec.

Has anyone else heard of such a thing?

I don't know.  What year is it?  

2008

The cams have IN & EX cast into them correct?  

No eBay APP ID and/or Cert ID defined in Kunena configurationExcept for the clear markings, I can see how someone would mix them up.  I have no idea if they should work swapped, though.
Photos #6 thru 10 clearly show the IN & EX.

My bad, everyone.  While the etching on the cam sprockets are switched around for some reason (which is what I was looking at), the cams themselves, which are etched along the body, had been correctly installed.  A check of the service manual says that the sprockets are identical so I don't know they are etched "IN" and "EX" at all.  This has been a senior moment.

I would like to put to rest the myth with regard to checking valve clearances, "as long as it runs good, don't mess with it."  It ran good, my son was blowing off the tune-up, most of the valves were tight.  With regard to "properly adjusted valves make noise", yes, and valves with excessive clearances do also.  The valves in the new engine in my Honda CBR250 were making noise after breaking it in and I found all were loose.  Now, it runs quieter and has a bit more power.

In short, check valves clearances when you're supposed to then go back to riding them hard.

Or pleasurably aggressive. I don't know what riding a motorcycle hard means. doh.

As for the camshaft sprockets, the parts diagrams show that they have the same part number, so technically it probably doesn't matter if you swap them.  But since they're marked, I'd want them "correct" to avoid any confusion.  such as here. ha ha.