When block picking stone bricks (ID 43:5) I am given what appears to be stone bricks (ID 43:5) but when placed a double stone slab appears (Item ID 44 i think)

When block picking (default button 3) stone bricks item id 43:5 i am given the texture of 43:5 (stone bricks)
But when placing this item double slab item id 44:0 is placed (in multiplayer hosted server that i admin)