I my last long commentary I describe how this variable works, when it doesnt exist and when does, etc.
No, this will not works - and it highly depends where this command is executed.
This variable exist on line with first G41, not sooner, never.
So this is useless for you.
I suppose you want DCD only in case when you are machining with cutter compensation.
You have to find other variable and do checking by another variable if cutcom is turned on.
(But if even if cutcom is turned on the path dont have to be generated with cutter compensation in some cases, but it doesnt amtter I think.)
You can output it by your command but in the start of operation mom_cutcom_adjust _register variable doesnt exists - you will find that variable exists on the G41 line.
Type to your tool cutcom register for example 777 and postprocess with debug.
Then browse debug files and look for 777. The you can find more varibles with this number.
And you can test them if they exist.
If you want to find some variable what can tells you if operation has path with cutter compensation
do postprocess debug with cutcom on and second time with cutcom off.
Compare debug files - you can find some toggle switch variable etc..