There may be some capacitor values slightly different too but changing the SAW resonator should be sufficient. The antenna is the 'U' shaped track with the part number inside it. Note it is double sided. If it works with just the SAW replaced I would be inclined to leave the rest alone. The range may be slightly shorter than normal but probably still adequate. To optimize it, you would have to shorten the right side of the 'U' as shown in post #4 by about 20% (on both sides of the PCB) but the exact best length would have to be found by experimentation.
Brian.