Year of manufacturer should be on the data plate stuck on the back part of the cab above the drivers seat.

Also check the grey mast information sticker stuck on the side of the mast as the date might also be on there, I know the mast date is on the newer Reflex, cant remember if its also on the older ones.

There should be a warranty sticker on the truck somewhere ( maybe inside ) with the cutoff date when the warranty ran out, it will be a year before that date.

Going by the serial number I would reckon between 1998 & 2000 as a rough guess, sorry I cant help any more then that.