The S4's got the new shape tank, but not sure of date they became available. Most other monsters with the new tank shape 600/750/900 left the factory late 2000, but were not registered until 2001. The 620's appeared later than this once the 600 was phased out.
Both my own 900ie's were registerd in 2001 & 2002, but actually left the factory as 2000 spec bikes. I found this out the hard way after ordering a new rear brake m/cyl for a 2001 bike, and it didn't fit as mine had a 2000 spec one fitted!
Both my 900's have the later tank shape.
[Edited on 1-10-2005 by Gary T.]