That is correct starting with V 1.30 there is a option not to lock but it is for one version of the PCM and I am not sure what GM cars/trucks uses that PCM and for what model years starting in 2005 models.
If the owner of the car has LS2edit that is one thing since they could control locking or not but most tuners ( I don't) do lock their tunes leaving the customers screwed.