Some yes, others no. You're going to have to do the research ahead of time and look at all the programs you think you will apply to. Most should have information on their website about their application requirements. If you see too many that only take USMLE step 2 then you will have to decide if you want to take it or not. Also look at how many current residents are DO's as some programs will have none.
As a generality, it is probably harder for a DO student to match to TY then preliminary medicine, even though they are about the same.
If you feel like taking USMLE step 2 will boost your application and calm some anxiety about matching then I guess you should take it. Just make sure you do well on both exams as most programs will expect your COMLEX to be good regardless of how well you do on USMLE.
