Ok i have a very quick question, i am going to sell my ipad and it has 4.3 Gm seed running on it. will that expire or have to be updated if that is the one that becomes the version released to the public. and if it is not he version released to the public an it just be updated when the 4.3 comes out on the 11th?
No, they do not expire and you probably won't need to update to the final version. A GM is normally the final version. There have been some exceptions in the past, but this time it seems that there won't be any changes.
If there is an update, it will install on top of the GM seed. Most likely (unless a show-stopping bug is found), this will be the version released next Friday.