You can use the cams. Most likely you will need to use all of the timing equipment from a 98 with them, as the change to narrow chains and sprockets probably came part way through the 99 model year. If you need the wide parts, you will also need the appropriate timing cover.
I'm not sure, but I suspect that the change happened at the same time as the change from return fuel system to returnless fuel system.
Check the build date and post it. Maybe someone knows the changeover date (a dealer parts person should be able to look it up). The build date is on the VIN sticker on the driver's door.
