What's the best way to fix this?

So I had a friend come to me and ask me this. I honestly have no idea. Anyway, he has a gun with a laminate stock on it. The problem was that someone took a sharpie or similar or that's how it looked and marked some of the lighter spots with it. We have no idea why, and honestly it didn't look the best. We tried to get it off with water, but had no luck. He ended up using some Krud Kutter http://www.krudkutter.com/ on it and of course it took the marker, or whatever it was right off. The issue is that he is afraid it took the finish off the gun too. In most of the spots he rubbed it heavily to get the marks off, you can tell no difference. However, there is a spot it may have gotten on that you can kind of feel the wood in. He can't remember if it was like this before using this stuff nor can I. So did this stuff most likely strip the finish off? If so, what does he need to do to prevent having issues in the future, or is he pretty much screwed?

Is there a way to tell if the finish came off? Visually, it's hard to see any difference from the rest of the stock. Infact, even in bright light you can't tell any difference. He is just wondering if he should get it refinished as he isn't comfortable doing it himself, or if he should just leave it like it is.

I will ask for pictures, however, having seen this, I know you won't be able to tell much from pictures as you can't tell in person if it's been removed or not. Or at least I can't as it looks the same as the rest of the stock.

Okay, so I talked to him and told him your suggestions with the water and he tried that and said he couldn't see a difference at all when putting a drop on the spots he messed with, or on the spots he didn't mess with. He also let it run and it looked the same when it ran. He said he let the water sit for maybe 15-20 seconds and it just stayed there as a bead in both areas until he wiped it off.

Here are also some pictures.
This is the side that wasn't messed with.




Now this is the side that was messed with. BTW the lighter spots were already there. That's what someone had tried to cover with a marker or something that looked like a marker. When he wiped the marker off it looked lighter like this. You could tell it was like this underneath the marker. So he didn't make the lighter spots, but the rest around that area is where he used the Krud Kutter.

Like I said, neither one of us can tell that anything is missing, he was just worried and wondered if there was a way for him to make sure he didn't take the finish off.

I keep thinking you should be able to see or at least feel that the finish is gone. Am I correct in thinking this?

Well, you can feel the wood grain in one spot, but I have a feeling it was like that before as there are other spots you on the other side that you can feel the wood grain too. Does that mean since you can feel it the finish is gone right there? It's also not where he says he scrubbed that you can feel the wood grain, but he said some of the liquid cleaner might have gotten there.