Marine 360?

Hi, I have got a 360 bare block that I'm starting to think is or was a reverse rotation marine one, the bore size is +.025", that is weird enough, the stamped # on the front of the block is 5 or 6 numbers stamped vertically instead of just under the deck. What has pointed me to marine is the bore wear, what little of it there is, is on the minor thrust side of the bore. Anyone had experience with this stuff ,and if so are there any other differences that would preclude using it as normal rotation ? Thanks .