The Gong Mandala promo poster you might have been lucky and scored at a gig or blagged from a Virgin shop in 1975. Originals fetch a high price if you can find one. This version is beautifully lithographically printed (strong light-resistant oil-based inks) on heavyweight 250gsm paper ideal for framing.
Daevid's wonderful Flying Teapot Spotters Scroll was available as a freebie from Virgin Records and was advertised inside the Flying Teapot album. It was available for perhaps a year in 1973/74. GAS printed some more in the early 1990s.
The Gong Mandala promo stickers appeared here and there in 1974/75, and the Teapot sticker we produced for the 'Love From The Planet Gong' box-set extras.