This may have already been discussed (apologies but I couldn't find anything on it) or be better in General Discussion but the title is the question.

The OK book allows for a good number of units to be taken as DoW in other armies. I don't own all of the Army books but do any of the ones published after OK actually allow for DoW.

None of the post OK books I have (namely Empire) allow for DoW to be taken as rare choices.