I also think it's worth noting that all of the classic armors we've seen leaked so far (1, 5, 41) were destroyed in Iron Man 3, which can mean one of about three things:
1. Time travel or BARF is used in Endgame.
2. The set is actually based on Iron Man 3 rather than Endgame, which honestly would be amazing if it meant we're gonna start getting new sets from past movies (I'd love to see some Winter Soldier sets!).
3. The set is based on a new hall of armor that takes place in the "present" (in regards to Endgame), and the inclusion of old suits is just a stylistic inclusion on the part of LEGO. I think this is plausible, as Tony's main suit in Endgame is allegedly called the Mark 85, which would leave plenty of room for a new hall of armor. Plus we've seen concept art of Tony in what appears to be a lab with multiple Iron Man suits, which may have been for Endgame rather than Infinity War.