Mmhhh.... See these parts:
http://www.bricklink.com/catalogItem.asp?P=14769pb004
http://www.bricklink.com/catalogItem.asp?P=4150pb148
Images were supplied by the same guy so we can be pretty sure that both type exist. But Brickset list only one design and item:
http://brickset.com/parts/design-16424
These design numbers are those of patterns, not shape if they are equivalent.
http://www.bricklink.com/catalogItem.asp?P=14769pb004
http://www.bricklink.com/catalogItem.asp?P=4150pb148
Images were supplied by the same guy so we can be pretty sure that both type exist. But Brickset list only one design and item:
http://brickset.com/parts/design-16424
These design numbers are those of patterns, not shape if they are equivalent.