The GT2000/2000L/2000X all used the same motor.
The GT2000X has a larger bearing & spindle - if you look at the GT2000X the truncated pyramid below the spindle is steel. On the GT2000 & 2000L the truncated pyramid below the spindle is brass. Source is actual TT's not vintage knob.
The gunmetal platter YGT-1 was an optional upgrade for any of the GT2000 series.
Check out the start up times - with the YGT-1 on the GT2000X it takes about 4 times longer to get to speed than with the standard platter.
Basically the GT2000X came standard with same motor, bigger plinth, bigger main bearing & improved tonearm.