How much of a problem is this?

[mrtelefoneman1]

So I started to install pipes on my 01 Nomad with about 30k on the odo the other day and as I was unbolting the head pipes, I noticed this. Notice the oily film over the upper fins. Sorry about one pic being skewed. There is not a slimy mess, just a film like I applied Armour All or something. This is on the right rear cylinder and I also noticed the same on the left front. I know that it is oil but why? Any help is appreciated......MAS, DL...please.

Thanks in advance...Levi