I found an original color publicity photo from “I Love Lucy Christmas Show” episode (1956 ) of Lucy and Desi at buzzfeed.com and corrected the contrast, saturation and background lighting in Photoshop and below is the result. The blue of the walls and woodwork came up when l lifted the brightness  of the background  and it corresponds to the blue in another original color photo – seen below . The beige color walls often seen in colorized pictures of the set may have been picked up from color photos of the Ricardo’s first apartment in the early episodes.

The color used for the Ricardo’s second apartment appears to have been blue at the time these photo were taken. It makes sense that there would be a color scheme change when moving to the bigger apartment and getting the new furniture.

I believe this photo has colors that are close to the original set colors because the Bolstad picture on the wall is correct and the rare seated chinese man statue to the right of Lucy has colors that are similar to an original one from the same factory.
Happy Holidays!