The only difference between the pre-2004 5 wire RR and the later 7 wire RR seems to be that in the later ones Suzuki doubled up on the number of contacts in the 12V DC plug - obviously to spread the electrical load across a larger contact area and stop the 'melting RR plugs' when the contacts became a bit corroded or loose. The two pairs of positive and negative wires on the 7 pin setup go to exactly the same place in the bikes electrics and the 'direct to battery' loom from Electrex ( supplied with RR851 ) just takes them all straight to battery. So you could still plug in the stator and if you choose to use the supplied the direct to battery loom still plug in the loom without soldering anything - depends if you want to pay £90 for the much better 'series' RR... and your bikes RR plugs would be compatible with any 2004 ---> RR for plugs, just depends if they kept the same physical RR size as pre-2004 ( you can check that as the pictures shown with the RR851 have one that shows the physical heatsink and mounting slots dimensions )
https://www.electrexworld.co.uk/acat...Rectifier.html
The standard MOSFET shunt regulator for your bike is RR85 - same price as the series RR851 which is a much better RR than even the mosfet shunt one ( the series type runs cooler and easier on stator coils ). the later RR is 30mm longer ( 110mm ) and the mounting slots are min 67 and max 91mm, the standard one pre-2004 is 80mm long and slots are min 53 max 66mm, maybe you can dremel a bit out of slot ( couple of mm ) to fit longer one if space allows. The width and height of both RR the same at 80mm and 30mm
https://www.electrexworld.co.uk/cgi-...2ehtml#SID=439
JUST RECEIVED MY RR851 IN POST ( ORDERED 6TH AUG ) AND THE 'STRAIGHT TO BATTERY' LEAD IS NOT INCLUDED IN THE PARCEL, DESPITE BEING SHOWN IN PHOTO WITH THE RR. IT REALLY IS AN 'OPTION' THEN.