Can't tell ya what the actual Ohlins shock model # is but as far as I know the same spring fits all of the pre 2006 Ohlins equipped units. I know for sure '03, '04, and '05 cuz I've interchanged them. IIRC they went to Sachs in '07.
I have the 5.6 spring that came on it ('05 MC 250) and I'm currently running a 5.2 that I took off an '03. At 190 lbs. w/o gear I think a 5.4 would work better...
The numbers on the 5.6 spring I have read - 00596-12/56 L344
Last time I went thru this no one on here really knew exactly what those numbers meant. One would think that L344 relates to length but this spring measures 271.5 mm.