This looks like a bug to me because the **[documentation][1]** says that **Rename** on the Result shortcut menu ...

> Renames the result. The default name is the tool name followed by the
> time and date.

I would recommend reporting it but in the meantime I would suggest that **Copy As Python Snippet** might be an alternative and perhaps better way to record results and re-run them later.


  [1]: http://resources.arcgis.com/en/help/main/10.1/index.html#//002100000013000000