I couldn't tell you if a remap is necessary in your case but, if you need one, Rexxer can provide a reflash for both the Euro 3 and Euro 4 821. If you want a definitive answer, I would contact Neil at Cornerspeed (01623 238944)
http://www.cornerspeed.co.uk/
He's very knowledgeable about fuelling matters and Ducatis in general and he offers a postal reflashing service.
Note that the Rexxer reflash requires a 'seed key', whatever that might be, (Neil will know, I'm sure).