That bolt is not correct for Tinker's receiver, though it might work in a pinch if all you cared about was firing the rifle (assuming it headspaced OK). I would not do it.

The bolt on auction looks like an MLM MkII bolt, so it would probably lack the cutouts for the safety lever to work. Also the bolt head is completely different from the MLM MkI and MkI* bolt, which is what Tinker needs.

Attached is an image of what the proper bolt would look like.

Cheers,
JC