Originally Posted by seagrade

The two photos are from 1980s Merckx catalogues, the first from the early 1980s (production started around 1980) and which shows the EM80 decal style. This was the only style in common usage before 1986 and would be period correct for the repainted blue frame. The second photo is from around 1987, and shows the EM86 decal style introduced in 1986. Interestingly the Corsa Extra and Criterium frame at that time had EM86 decals while the Corsa and Strada had EM80. Possibly to differentiate the less expensive models or to use up old decal stock.

The blue frame in the centre of the first photograph would indicate yellow EM80 decals with black outlines would be a good choice for the repainted blue frame.