I think that would be a pretty good idea, but at this point in time it would be kind of difficult to go through every doujin and tag them. It could be done gradually, but it could take a while. Unless of course there is someone willing to undertake such a mission, in which case a new title might be appropriate.
For starters, how about writing the tag in the manga description, rather than waiting for the admin to update it with just one measly tag, that will take hours to tag hundreds of doujin. I'll do it, if there are others willing to help.
I think this is a good idea, adding a checkbox and a tag that says "Censorship".
I have most of FAKKU's manga on my hard drive anyway, 99% being the same version. I could crawl through and add the censorship status to everything I've got in a few hours. Jacob would have to enter in a new SQL entry, and since I don't know the structure of his SQL database, I can't say how difficult that would be.
Uncensored isn't hard to find. Just guess that most if not all of the Japanese language manga is censored and look only towards the English translations for decensoring. All of FAKKUs releases are uncensored.