Hi Mf, It doesn't look like you can modify a standard catcher to fit the Auto Drive VC, I don't have a standard VC catcher here at the moment but the red arrow shows how much the standard catcher would need to be modified to clear the axle and gearbox.
I have seen a lot of the standard VC mowers for $10 or less,got one for $1 a few weeks back,you could strip the axles out of the standard VC and fit them to the Auto Drive after removing the auto drive axles then fit the standard catcher.