Hi Noah and welcome. The finish is actually Manganese Phosphate and a listing correction has been sent to Buds. Anyone can send a website correction at the following link as well: budsgunshop.com/contact_us.php?printForm=reportError --------- cheers and stay safe!

Tisas web site says phosphate for this upc
Action Type: Semi-Auto
Operation: Single Action
Caliber: .45ACP
Frame/Receiver - Slide Finish: Phosphate
Sights: Fixed - Enhanced GI Style
Optics Ready/Cut: N/A
Capacity (w/Included Mags): 7 + 1
Barrel Length: 4.25"
Threaded: N/A
Barrel Finish: Phosphate
OAL: 7.92"
Height: 5.3"
Width: 1.41"
Weight (Unloaded): 2.1 lbs.
p
https://tisasusa.com/1911a1-tc-45/