Aeon418
It most certainly could symbolize an upright pentagram.I read that the goat with it's horns symbolizes a reversed pentagram, if the card is reversed could it symbolize an upright pentagram instead, or is this just crazy thinking?
But there's a subtle twist on the Thoth Devil card that a lot of people miss. In some other decks you see a Devil with an inverted pentagram head, holding an upside-down torch. If you flip the card around the pentagram is upright and so is the torch. This tends to result in very dualistic, good-versus-bad interpretations. But on the Thoth card, even though there is a suggestion of an inverted pentagram, the torch(Phallus) is already upright. So if you flip the Thoth Devil the pentagram is upright, but now the torch points downwards. This indicates that neither direction is good or bad in itself, it's merely a change of focus. This may be what the card is trying to say in the context of your reading.