Ok since gog is selling the ad&d games I taken the liberty of mentioning the games are on gog (like on the stronghold page) and added a link does gog mind ?

You should contact support.
http://www.gog.com/support/contact

Unless I'm missing something here, I don't see why you would need GOG's approval.

well some sites view it as unasked for advertising

Yup - and others may see it as misinformation (unless they do it). As I said, contact support (maybe with a copy of what you've written as well) and see what they say. I doubt (legally) they can prevent you from posting it, but they may also offer additional info. Don't know unless you ask! :)

If you're posting this on Wikipedia, there's no problem. Its not like GOG owns the Wikipedia page and change what they will. Though do note that your edits may be changed by other members, is all.