The "variant" press?

There is a S#%tload of threads to  sift through, finding  an answer. Perhaps someone can provide a explanation to the my question.

Where in line does the "variant" stand from a "1st press"? I'm not clear on the lineage of the "variant."

Recent buy is this promo copy of Warren Zevon's "Excitable Boy". One of those artists I just never got  around to listening to. I've found a "stamper" level(at least one worthy of consideration, since I don't have 5 others to compare)
https://www.discogs.com/Warren-Zevon-Excitable-Boy/release/6684772

Was there an actual record pressing facility in Compton Ca? California long timers may have an answer to this. 
Interesting find, as I see the matrix ending with the "W" indicating a Compton, Ca issue. Compton is a neighboring city to my hometown Long Beach. I can't find definitive info indicating an actual LP pressing facility that was in Compton.

This album has an all star supporting cast

• Karla Bonoff – harmony vocals on "Accidentally Like a Martyr"
• Jackson Browne – guitar, harmony and backing vocals
• Luis Damian – jarana on "Veracruz"
• Kenny Edwards – bass guitar on "Veracruz", "Tenderness on the Block" and "Lawyers, Guns and Money"
• John McVie - bass on "Werewolves of London"
• Mick Fleetwood – drums on "Werewolves of London"
• The Gentlemen Boys (Jackson Browne, Jorge Calderón, Kenny Edwards, J. D. Souther and Waddy Wachtel) – backing and harmony vocals
• Arthur Gerst – Mexican harp
• Bob Glaub – bass guitar on "Roland the Headless Gunner", "Excitable Boy" and "Nighttime in the Switching Yard"
• Jim Horn – recorder on "Veracruz"; saxophone on "Excitable Boy"
• Greg Ladanyi – bells on "Nighttime in the Switching Yard"
• Rick Marotta – drums on "Veracruz" and "Lawyers, Guns and Money"
• Jeff Porcaro – drums and percussion on "Nighttime in the Switching Yard"
• Linda Ronstadt – backing and harmony vocals on "Excitable Boy"
• Leland Sklar – bass guitar on "Johnny Strikes Up The Band" and "Accidentally Like a Martyr"
• J.D. Souther – backing and harmony vocals
• Manuel Vasquez – requinto on "Veracruz"
• Waddy Wachtel – guitar, synthesizer, harmony and backing vocals
• Jennifer Warnes – harmony vocals on "Excitable Boy"

Fantastic album, also audio rig show off worthy.