I don't think Tolkien's description of Minas Morgul was tangeable enough for PJ's version to be called "definitely different". The city's "glow" was described thusly (is that even a word?):
Yeah, PJ's Morgul is definately different then Tolkien's morgul
All was dark about it . . . but it was lit with light . . . Paler indeed than the moon ailing in some slow eclipse was the light of it now, wavering and blowing like a noisome exhalation of decay, a corpse-light, a light that illuminated nothing.
Clearly this is all beyond the bounds of physics (or at least, what I know of them) and is more metaphorical than anything, thus leaving it open to interpretation (as is the case with a lot of Tolkien's descriptions). The words I bolded are what leads me to believe that the light was greenish. Furthermore, we have this quote:
Then [Gollum's] eyes shone with a green-white light, reflecting the noisome Morgul sheen perhaps. . .The problem here though is that Gollum's eyes are described to have a green glint to them. But I think it's still clear that Tolkien was trying to say that light coming off Morgul was green'ish, else why would he even include the colour in the sentence.
The only problem is that we are later shown that Minas Morgul's "beacon signal" colour is blue... Kinda odd to have two colours.
My lord that was horribly nerdy.
Anyway, great model. Loving it!