Today, I was pleasantly surprised to find the Griffin Mountain (Runequest, 1981) that arrived in the shop is the licensed UK edition by Game Workshop. I was unaware this version existed.
I first noticed the quality difference before anything else. Many (most, really) of the Griffin Mountain books I encounter have cracked bindings, with pages either threatening to come loose, or are already loose. Chaosium’s printer used a low-quality glue that hasn’t stood up well to time.
In contrast, this Games Workshop edition is firmly bound. The paper quality seems better as well, semi-glossy.
As far as I can tell, the content is a page-for-page duplicate of the Chaosium printing.
The GW map is smaller (15½” x 23¼”, vs. 20″ x 30″ US map), and likewise of a glossier paper stock.
EDIT 12 May 2021
Griffin Mountain Poster Map (both sides): Balazar & Elder Wilds. Click for full image.