DT175 petcock replacement

Hey there! Looking for a new petcock assembly for what I think is a '78 DT175. Everything I see on **** uses 2 screws to mount it to the tank (see pic below) but the one on my tank is a threaded nut on the top.


NOTE: The picture above is the type that I DON'T need (can't find a pic of the one I do need)

Anyone know of any other petcocks that'll work for my application?

Thanks!