cut the spring down? it's been powder coated too then as they're yellow. more likely it's been changed as the R1 spring is a 7.5 and you need about a 14 for the FZ6.
Seems a lot of money to me for a used R1 shock. Kais charge £275 to revalve and respring an R1 shock, add on the cost of one £50? - and you're getting into premium shock money.