All versions of Metallica are SAM. None of them are SPIKE. Also there is no Vault edition of this game. The original run of Pros had incadescent lights for GI....LE and Premium were all LED.
It was perhaps 1-2 years into production they introduced the LED pro which is a tremendous upgrade with LED’s. Now even though it has LED’s it’s not the complete lightshow that is on the LE/Premium versions.
It was also at this time the Wood Backbox was changed to a Metal back box and it has an angled speaker panel. The angled speaker panel is your first clue if it is an original run or later run game. Original run Pros, Le/Premium versions all had the straight speaker panel and it has square holes for the speakers.
I believe all the first/early runs had very few issues with playfields. Later runs with the metal backbox had a period of hit and miss playfield issues but it seemed ALL games from 2015-2017 were hit and miss on playfield issues. I believe Stern took care of people with major issues. It seems current runs have had very few playfield issues if any.
If you are looking for a Pro just buy a NIB NOW while you can. If you are looking for used inspect the game in person and make sure it’s what you want.
Now me personally I prefer the first run wood back box but mine is a premium. Since you are looking for a pro the LED Pro is the way to go unless you have a lead on an original run Pro and plan to add LED’s...but for all the effort adding LED’s I would just find an LED Pro.
If you have more questions go ask in the Metallica Owner’s Thread.