Yes, but, as was discussed earlier the descent was to be coordinated with McMurdo radar, not controlled by McMurdo radar. To even coordinate they would have had to have been identified.
The other descent requirements re 20DME from the TACAN and to the South of McMurdo would have, as planned kept them well clear of Mt Erebus.
There would have been a cone overhead the radar when no return would have been possible, but the radar operator would have known that, and it was nowhere near Ross Island and there for Mt Erebus.
The other rules pertaining would have been below 3,000 AMSL or 1,000 AGL, whichever is higher, you only need to remain clear of cloud and in sight of ground or water.
I do not think anybody in their right mind would consider these requirements could be applied to a DC10 at 260kts 1,500ft, anywhere, let alone in Antarctica in the weather conditions prevailing in McMurdo Sound, and what they had been advised was current at Scott Base, or any other sightseeing position on their agenda at McMurdo