The whole track was recorded in D (whole step down) so it was easier for them to play. Then tape was sped up to match the tuning. You can check Circle of Sound on YT. Not that they couldn't play it superfast live.
It's amazing what 5hz does. I can't explain it properly, but this sounds a little....not more energetic, but less...gloomy? I can't put my finger on it. But it's amazing the difference a slight tuning adjustment makes to the feel of the song.
When you've listened to the original for a long time, it's the 440hz version that feels "out of tune". It also depends on what song are you playing. Some songs sound better at 440hz and some at 435hz. The songs in Megadeth's Peace sells are even tuned lower than 435hz but still in E
Could you maybe share with us a video on how you did this? Literally I've been playing along to metallica albums for 26 years and this is was the most fun I've had in a long time nothing like those chords ringing perfectly in tune. Please do more of these ! Literally everything recorded to analog tape originally seems to be off tuning wise.
Get Audacity, import the song, then there's a function named something like "pitch shift" (without tempo change) - use that, and there you go, just gotta tweak it until you hit what you're looking for.