The MODX definitely has saxophone sounds… they are not exactly the same as in the MO8 (2005) - when the AWM2 engine used in the synthesizers supported just 4 Element Waveforms (oscillators) per instrument sound. In the MODX the programmers have more freedom when it comes to the number of Element Waveforms they wish to use in creating the instrument sound. This greatly expands the types of things you can do with the sound as you perform (adding growl, legato transition between notes, etc, etc).

The MODX can have 8 Element Waveforms per instrument slot (called a Part) and the programmer can use as many as 8 Parts to create a playable sound.

So all new programming is done on the instrument sounds in the current models. If you are asking could you load a MO8 Voice into a MODX… not directly. I have converted both Motif ES (2003) and MO8 (2005) Presets to a format that can load into the MODX.

Typically Yamaha puts a “lookup table” in the next model… so the MO was based on Motif ES sounds, ES sounds could be read and loaded into a Motif XS/XF — When a different, newer Waveform was substituted the “lookup table” would make the appropriate substitution. The Motif XS/XF sounds can be loaded into the current synths because they include the “lookup tables” for the previous model. So even if not exactly the same, their is a very close approximation.

The big changes in the Yamaha AWM2 (sample-based) engine took place in 2007 (Motif XS) where it went from 4 Oscillators per instrument to 8 Oscillators with Articulation Control and again in 2016 (MONTAGE)… where the number of Oscillators in a normal AWM2 instrument sound balloons to a maximum of 8 times 8 Oscillators (64).

Extra Credit:
Here are a couple of articles that go over a Tenor Sax sound (combined with a rhythm section) read through it - you’ll get an idea of how much deeper the control over playing the Sax sound extends in the current engines.

Link — Tenor to the Max
Link — Customizing “Tenor to the Max”