Distribution Block,72 Swinger

For two days now, I've read MANY threads on the Distribution Blocks. And I've ended up more confused, than before.
On the inlinetube page for the block, I see, on the left, what appears to be the correct block, for my 72 Dart. Yet, it shows and says,(and or) two other blocks. It's like they are saying that I have one of the other blocks, also. The only other distribution block, that is in my brake lines, is the one on the rear diff housing. I'd really like to order a new one, as I'm ready to install all new brake lines. Is the one shown on the left, the correct choice?
Below are the two blocks I have, now and a link to the Inlinetube product page.
Thanks

















http://www.inlinetube.com/Prop%20Valves/BLK245.htm