The NASA meatball seems like the wrong era. (I know that's illogical, given that it would take years to even build the space station that the round-the-moon ship is launched from). I've tried the USAF roundel, though. It's hard to decide how far to go in making details up.
...The Roundel I didn't even consider, most likely for the possible reason you state in the fact that even with proper funding it would have most likely taken WVB and his fellow "Paperclippers" well into the late 60s if not the early to mid-70s to have pulled off a lander such as this. Whether the N.A.C.A. would have evolved into NASA or not is a good point of debate, but the Air Farce logo is probably a safer bet. I'd almost be tempted to add on an N.A.C.A. logo underneath or on the lower sphere, but as has been pointed out numerous times over the decades, that level of involvement was not "the Langley Way".
...One thing that's come to mind, tho: in OTL, we named our landers. Any thought about what to name this particular lander?