Surveyor

Tucked in between the two Mars probe exhibits is an engineering model of the Surveyor moon probe.

It is displayed, more-or-less, in its landing configuration: The solid retromotor has been jettisoned and two of the three landing legs are deployed. One leg is still in the stowed position, but only because the exhibit area isn't large enough to allow it to be deployed.

This engineering model would appear to be NASM catalog #A19710065000.