Is it still tape sealed? If not, has the wampa yellowed like most do?
If you can prove the wampa is still bone white, it'll add a crazy premium to it. As in probably double what a tape sealed boxed one would be. Just don't cut that seal to find out if it's still taped.
I think a fair few collectors prize those debut first issue boxes, for me that makes it worth a bit more, I'd say an £80 piece (unsealed but mint/complete).
There are usually indicators for most vintage vehicles or playsets.
In the case of the Wampa the tell is in the title. The first issue is simply called 'Wampa' then afterwards this was changed to 'Hoth Wampa' (the figure being dragged by the Wampa in the photo also changed from Rebel Commander to Luke Hoth).