I'd rather see the green checkmark used for "same hash" --where the content is the same but the name might differ.

It is handy to know that a file has the same name--how about a yellow check for that?

Yellow checks would only turn green once the hash is retrieved from the host (i.e, no need to retrieve the hash unless the user explicity asked for a check by initiating a download).

Then a "rename" dialog would be more useful than the "overwrite" one.