First 850 was 300000. There are some odd mixes in the 235000 area, some 850's & some 750's but other than that a 1 or 2 at the start is a 750 and a 3 means 850.
Mar 1973 220000 Roadster MK V
Mar 1973 220000 Hi-Rider MK V
Mar 1973 220000 Interstate MK V
Oct 1973 230935 Last 750cc Commando
Commando 850 Apr 1973 300000 First 850
Sept 1973 306591 MK IA 850
Jan 1974 307311 Mk II and IIA 850