There are no OMT questions, so it is possible. I've never taken both so I can't tell you. However, the allopathic book I study from seems to hit it on the nail.
No. The osteopathic inservice exam questions are written by attendings at the DO programs. No OMM questions and the content covered is the same as on the MD version so any of the standard review materials are useful. I always used the Rivers materials and did well.