One of the most stubborn of design origins in the SWORD fleet os PROBE FORCE 2, which is shown here in both it's Century 21 and Tarheel boxes [Moonbase collection].
The toy space-plane and the box art in close-up above and below show the PF2's distinguishing features including a thick main body, deltoid wings and two top rockets/foreplanes.
Although not wholly convincing there are some similarities with the 1961 AQM-37 Jayhawk missile of the US Navy as seen below.
This artist's impression clearly shows the Jayhawk's thick body, deltoid wings and a pair of small foreplanes. It also clearly shows the main difference, the missile's pair of rear arrowhead wing fins.The Jayhawk is popular with modern rocketry enthusiasts as shown here.
I feel that there's something here but it's not enough to pin down PF2. This drawing of the Jayhawk show that the rear wing fins [proper name?] are clearly an important feature and oddly enough one which we associate not with Probe Force 2 but with Task Force 3 pictured at the bottom. Interesting but not conclusive for either. The search goes on!