Probably another stupid question but I am in the process of getting the Light up Mace Windu missing his purple light saber.  Bricklink treats the figure as a whole without inventorying him.  Is the trans purple light saber blade unique to the figure or is it the same as the rest of the purple light sabers?

The "trans light-purple" is different than the "trans-purple" - it's a much less pigmented colour so that the weak light would show through it.   It's supposedly unique to that figure & is not listed as an available colour for the Bar 4L #30374 separately but there are many available on BL (though allot of them are mis-identified colours) so it's likely not as unique as intended & has other sources than just the figure.   

 

Also within the trans light-purple bars there is a variant that is frosted too - it gives the glow a much more muted effect (not as nice really).

The "trans light-purple" is different than the "trans-purple" - it's a much less pigmented colour so that the weak light would show through it.   It's supposedly unique to that figure & is not listed as an available colour for the Bar 4L #30374 separately but there are many available on BL (though allot of them are mis-identified colours) so it's likely not as unique as intended & has other sources than just the figure.   

 

Also within the trans light-purple bars there is a variant that is frosted too - it gives the glow a much more muted effect (not as nice really).

Interesting.  I am trying to get the exact blade and I am not sure if the ones on bricklink are the actual "trans light purple".  Suppose I could ask the bricklink stores.

I used to have one and it was definitely lighter in color than the regular purple version.