Any #lockpicking nerds out there who can help me identify a padlock?

It's a hardened steel body U.S. Lock, which appears to be a clone of an American 780 series or similar. The only identifying marking is ”XGI" on the back of the body.

I'm currently in the process of de-rusting the body and shackle after picking and disassembling it, as this lock was sitting outside on the latch of the back yard toolshed for what looks like several years before I came along. My roommate claimed the lock was here before she moved in six years ago, so ofc she doesn't have a key. 

@foxyloon might be a series 5000/5100/5200 American Lock;
From what I can tell from eBay search - they look like military padlocks. I think the three letter code is a cipher for the date of manufacture. I'm not an expert, however.
It might also be a series 700 variation; too. Hard to tell without side by side. Saw a variety of vintage ones on eBay

@null_aleph  

All of those seem similar in profile. Definitely should get measurements of this one soon, I think that'll help narrow it down. I wouldn't be surprised if this was a government issued lock for a serviceman, as that's true of one of the previous folks who lived here. It was being used to lock up an old toolshed in the back yard, hehe~

I'd like to repin it and make a new key for it, especially because it only has five out of six pins currently. Maybe add one of those core bypass guards if I can.

I'd need to find a shop that can do that kind of work, though. I don't have the tooling for that. 

@foxyloon if any of the hackerspaces in your area have a 3D scanner, you should be able to get very accurate measurements on it and compare those against the Legacy measurements. Maybe overkill? Yeah.