The recall is good forever, meaning no expiration date but, it's a different story for the parts needed to do it, the manufacturer do not have a obligation to stock them forever and once they are NLA ,you're screwed.
As some other have suggested, you should get all the recall parts for free (it's what I did for #999 on my 00GTS) and just keep them.
For #998 you need a bunch of parts and the recall instructions is 74 pages long
Parts needed:
CAAP9984 DIFFERENTIAL FRAME BRACKET REPAIR PACKAGE
INCLUDE:
DIFFERENTIAL FRAME REINFORCEMENT PLATE
DIFFERENTIAL MOUNTING BRACKET
DIFFERENTIAL MOUNTING BRACKET GUSSET
CAAP9985 REAR TOE LINK BRACKET ASSEMBLY
CAAP9986 FUEL TANK ACCESS PANEL PACKAGE (GTS ONLY)
INCLUDE:
SERVICE PANEL
RIVETS (24)
CAAM9981 STEERING REINFORCMENT PACKAGE
INCLUDE:
STEERING GEAR CROSSMEMBER REINFORCMENT
RIGHT SIDE FRAME RAIL GUSSET
LEFT SIDE FRAME RAIL GUSSET
STRUCTURAL STEEL RIVETS (24)
CAAP9982 DIFFERENTIAL REINFORCMENT PACKAGE
INCLUDE:
DIFFERENTIAL SUPPORT BRACKET
DIFFERENTIAL "Z" BRACKET
DIFFERENTIAL SUPPORT BRACKET BOLT
DIFFERENTIAL SUPORT BRACKET NUT
STRUCTURAL STEEL RIVETS (10)
CAAM9983 STEERING GEAR CROSSMEMBER ASSEMBLY