Where Bandai and Tomino disagree, Tomino is wrong. Period. The fact is that many Gundam series were created without Tomino, and so his say on things is ultimately irrelevant. Bandai's official timeline has Turn A taking place 7000 years after UC, and G-Reco 1000 years after UC. Tomino might have intended G-Reco to be after Turn A, but Bandai's timeline trumps Tomino's. And remember that Tomino likes to fudge canon a lot. All of his novelizations of his Gundam works change the endings, sometimes significantly, and don't forget that he wrote and directed the Zeta movies, which don't fit at all into the established canon of UC. Considering how little attention Bandai gives to G-Reco (not a single 1/100, not even for the main suit...) I think it's safe to place it as "non-canon."

Where Bandai and Tomino disagree, Tomino is wrong. Period. The fact is that many Gundam series were created without Tomino, and so his say on things is ultimately irrelevant. Bandai's official timeline has Turn A taking place 7000 years after UC, and G-Reco 1000 years after UC. Tomino might have intended G-Reco to be after Turn A, but Bandai's timeline trumps Tomino's. 

And remember that Tomino likes to fudge canon a lot. All of his novelizations of his Gundam works change the endings, sometimes significantly, and don't forget that he wrote and directed the Zeta movies, which don't fit at all into the established canon of UC. Considering how little attention Bandai gives to G-Reco (not a single 1/100, not even for the main suit...) I think it's safe to place it as "non-canon."