I'm not sure either whether there is only this one plant of Roland Europe in Italy. According to this SOS article about the Roland history, there were five plants in Italy in 2005 (see section "Siel & Roland Europe"):
http://www.soundonsound.com/sos/jan05/articles/roland.htm

However, the bad news is that not only this factory, but the company headquarters of Roland Europe S.P.A. are also based in Acquaviva Picena, so I fear the complete subsidiary is being dissolved.
http://investing.businessweek.com/research/stocks/private/snapshot.asp?privcapId=8355130