I've had this come up a few times, and found some older answers to similar questions on meta.  
However I believe that the answer heavily depends on the current moderator staff, as they are the ones handling these flags.

When I see an answer in the [late answers](https://serverfault.com/review/late-answers) queue, I check if  the answer already exists.  
If the answer has been directly copied word for word from another answer on the same question, I flag it as `in need of moderator intervention`. As the other flags don't fit at all.  
I then add a link to the original answer.

Usually these flags get accepted.  
Other times the flags get declined, but the answer is still deleted.  
[![answers][1]][1]

As I am getting both positive and negative feedback on this way of flagging, I would appreciate some clarification.  

Should I:

 1. Flag these
 2. Downvote them (seems counter-intuitive unless I also downvote the original)
 3. Ignore them (also seems counter-intuitive, they are not contributions, but bloat)

  [1]: https://i.sstatic.net/zqZBN.png