It seems more and more that Gundam Reconguista in G is shaping up to be the prequel series to Turn ∀ Gundam itself. In episode 12, Happa tosses Bellri a backpack armor instruction manual that has a ∀ symbol on it. The same sort of manual can be seen in episode 3 of Turn ∀ when Rolan is trying to figure out how to pilot the titular machine (the only difference is that Bellri's manual is a literal book while Rolan's is a digitized manual -- the covers are exactly the same).
Both series reference Ameria -- Bellri is fighting for a pirate faction of the Amerian army while in Turn ∀ the conflict actually takes place on Ameria. The Armageddon referenced in Turn ∀ which seemingly laid complete waste to space colonies seems in line with it's explanation in the Reglid Century calender in G-Reco as well. The space colony Towasanga that has also been referenced in G-Reco which has produced the Gundam of it's age seems to be the space colony that was formed with the story of "Ring of Gundam".
The entire "Beauty Memory" from the "Ring of Gundam" might also possibly be the "Rose of Hermes" mentioned in G-Reco as well. It can be speculated that both are not only one and the same, but also a large data cache that has been collected throughout the entire UC calendar since Amuro Ray's time as a pilot. The "Rose of Hermes" might also have a tie to La Vie en Rose (and by extension Anaheim Electronics) from Gundam Zeta and ZZ.