Yes but which issue?

. . . Are plagerised works bootlegs in bookworld?

Well, presumable the contents should not change ( are abridged, edited,re-illustrated, Bowdlerised, translated, revised, prefaced, annoted should be different books) If it is just the jacket variation then that would not stop one for reading the wordage. Personally I am onto the large print editions from the library nowadays. Are plagerised works bootlegs in bookworld?

I meant "Which issue would you click on as having been read?"

Mmm...it's tricky.
Generally speaking, I'm sure most people would be happy to click a title of a book they have read, without having to worry about the edition. Readers may recall books from years ago, but not the edition or publisher. And there will be those who read a book and then pass it on, or view digital editions.
How an 'I've read' button could be put into practice, I've no idea - although there seem to be some very capable technical wizards on this site!

If we were to add a "Read It" button, it would work best if you could see everyone who'd read the same book, not just the same issue.

My point in a nutshell.

If there are multiple editions (even multiple publications) on here, which one would you tick as being Read?

In the section "Add Missing Info" I need option for adding language. For most of the books that I added, I forgot to specify this and now they are not listed in the main search lists. So many work for nothing.

If this is not possible in a day or two, I'm going to add them again so that they to be listed but then they all will be doubled in the database.