I've been rewatching the MCU and just randomly thought of this, hense why I'm 6 years late to this thread lmfao
But ok that would make sense, he reconstructed it for the armor gallery
I was confused because plenty of his suits get destroyed and I guess he rebuilds them cheaply, out of boredome and a coping mechanism, which in IM3 I think it is he says he's not the sentimental type, which is why he told Pepper to throw his old Arc Reactor away but she didn't which turned into his favor when his new one got ripped out of his chest.
Which I always thought was just odd as to why he'd rebuild his old suits if he doesn't care about sentiment.
But if he's doing it when he's not working on upgrades and what not to help cope with past trauma then that would make sense.