I know the clock removal/replacement process is different before and after 1997, but I suspect the bulb is the same. If the part number for the bulb/holder didn't change when the '98's came out, you can find it here. It only set me back $5 or so, and Lincoln-Mercury dealers also have this part.

//> //> //> //> //> Garrick 2006 Mazda6 Grand Sport wagon, silver, MTX I'll never forget you: Silver E0, #3895 of 6535, built 10/2/97