Thanks for posting the pics of the engine.
Here are a couple of pictures showing the drain plugs in a Survivor Engine. The driver side was painted as an assembly but the passenger side was not. The passenger side was left out so the VIN could be stamped on the Block. If that plug was installed, it would have been in the way of the apparatus that was used to stamp the Block after paint. Also shown are recent pictures of our Engine with the NOS Choke installed.