Yes, unless you disabled/powered off your spindle when using the laser, and disabled/powered off the laser when using the spindle.
You could attempt to wire a 2nd PDMX-126 output to the laser PWM input. Then you would need a Mach macro or script or something to re-configure Mach to change the spindle speed output from one signal to another. *IF* that can even be done at all. I fully expect that at the very least you would have to disable Mach, change the PWM mapping and then re-enable Mach. You don't say which version of Mach you are running (that is, if you are running a version of Mach). But either way, changing the PWM output pin at run time is non-trivial.