more or less...it was/is a brand sold by Marcel Calborn in SoCal (he's now located in Laguna Hills, I think) but these were made by the same hands/shops that built for Colnago. I believe he was a good friend of Ernesto and was a dealer of Colnago frames in the same shop that sold his house brand.
If you search the archives for both Celo and Calborn you'll probably find a bunch of info and background.