Yeah that's one of the things I thought. Technically though it would be different than smoke monster taking over bodies cause he doesn't take over bodies so much, for example Locke's dead body is still there, he just is able to appear in their form. If Jacob took over Sayid then he just took his actual body.

Ooh I just had a thought. I wondered why if for example the Smoke Monster took Jack's dads body then why was his body missing from the coffin when with Locke he doesn't take over his actual body but maybe Jacob took the body over and that's why the body is gone, he took his actual body like he took Sayid's.

If that makes sense.