Or if they use Gokaiger mecha footage (Bandai would presumably want to sell new Megazords for 2014) it'd look odd that there's a robot with a green arm, while there's still a black ranger as part of the team.
Wouldn't be unprecedented. MMPR season 3 used Kakuranger
footage and Zords but still used the Zyuranger
costumes, so the Pink Ranger had a white/red Crane Zord and a white Shogun Zord. They never made any attempt to explain or justify it.