Frame numbers over 1000849 (with build date post Sept 1997) should have it fitted, so yours should fit the bill.
Heres a little info:
REAS (Relative Absorber System) for comfortable ride and high handlings stability.
The REAS features an entirely new mechanism that functions not only to achieve a comfortable ride with a relatively small amount of damping force in cases like when both tires hit a gap in the road, but also functions to stabilize the body of the automobile against lateral "rolling" motion by adding a suitable amount of extra damping force and absorb the force acting in the lateral roll direction, as when cornering, when the pattern of depressions and protrusions in the road surface are different on the left and right wheel sides or when subjected to cross winds. Three main points of the REAS structure are as follows
1. The left and right shock absorbers have separate oil chambers with a REAS valve positioned on the connection flow passage.
2A single gas chamber is shared by the left and right.
3. Using the separate actions of hydraulic fluid and gas, a separating piston is activated by the coupled movements from the right and left.
Regards,
Gaz.