https://www.facebook.com/groups/TypewriterCollectors/posts/10163361603349678/
Merit Elite - foundry mark: 590<br /> Merit Pica - foundry mark: 378
https://www.facebook.com/groups/TypewriterCollectors/posts/10163361603349678/
Merit Elite - foundry mark: 590<br /> Merit Pica - foundry mark: 378

Royal QDLs from '56-59, though advertisement more likely from '57-58 due to the white.
Royal Green, Royal Star White, Royal Beige, Royal Gray, Royal Red, Royal Turquoise,
Add specifies the QDL is available in Canterbury Pica or Canterbury Elite.