98 200 Johnson cylinder head question

[Striper80]

I have a 98 Johnson Ocean runner on my boat that I purchased at the end of last season. I did a compression test and it was 100 across the board. I ran the boat twice last year and it ran well. I just finished going through the boat and fixing a lot of little issues with it so I haven't run it yet this year. While changing the plugs I noticed a bit of corrosion where the head meets the block on each cylinder bank. The lower plugs also were rusted. I'm wondering if this is normal or if I have head gaskets that are failing? I plan on keeping an eye on it. My last Johnson had a new power head on it so there was no corrosion. Thanks