+1 to George's comments. I would say that looks a rough old pump unless it's been shot blasted. They usually have a smooth die cast finish. If, as I suspect, it's a pattern pump of eastern European or far eastern origin, it may not be very precise as far as the bolt holes go. If you have your old one, offer it up and see if that fits properly, then make up your mind if you want to mod the new one and use it.