the foyles listing (no longer available) does not mention it is signed - but does state that there were only 1000 printed (at least we now know the print run):
Stunning limited edition of The Quite Nice and Fairly Accurate Good Omens Script Book Exclusive print run - 1000 copies only. White cloth boards with gold foil detail, Endpapers printed with gold metallic pantone, Extra material: four exclusive bonus sequences with introductions by Neil Gaiman and 'Scribbles on Set' from artist Lorna May Wadsworth - a series of bespoke black-and-white sketches from the Good Omens set, Marker ribbon, head and tail bands. Includes an introduction by Neil Gaiman about bringing Good Omens to the screen.
https://www.foyles.co.uk/witem/ficti...-9781472265227