DELTEGRA

How do I tell if Im getting a true jdm type r from the shop im getting it from? I know the intake is diff, the head, valve cover,but how to tell the block itself. Both GSR and R are stamped B18C, without taking the oil pan off, or the head is it possible? Also has anyone ever heard of any business taking the superior R parts out of the block and replacing with P72 Gsr parts. Im getting really scared to spend all this money on the R and finding out later that I got ripped!!!! Thanks guys and gals!!!!