John,
Received the ad copies you sent on the "Blue Spot" Frankfurt, Hamburg, & Koln "Mark I" radios, distributed by American Elite, Inc (NY, NY). Never seen this before. They are clearly Blaupunkt radios. Blaupunkt is German for "blue spot" or "blue dot", and American Elite has added the "Mark I" to the name of each. I didn't see any dates on the American Elite brochure, but the radios look to be "K" series radios which would make them 1956/1957 which goes along with the line drawing of the 56 Chev in the brochure. The guarantee cards seem to be dated 56 as well. Very interesting stuff.
CW