Rule #1 with original paint colors is when you want to be sure, go by the Ford paint code and year (from the Ford truck line, not car for Broncos), not names.
The name Ford used is sometimes not the same as what PPG, DuPont, Martin Senour or others called the same color.
Viking Red is however and original color for the Bronco. 1975 only, color code 6.
However, I'd have to look in my Ford paint book when I get home, but that color could even be the same formula as a red from another year or another model.
Ford used a color name and sometimes also a different promotional name which can vary by car to truck line, by year, or even by models of car or truck in the same year.
Bottom line, you could have the same actual color formula for which has different names and color codes from one year to another or even in the same year.
Here's a thread I started a few years ago with available Bronco colors by years. At some point I'll try to make a comparison chart of actual Ford paint base part numbers (formulas) to the various standard and promotional color names.
http://classicbroncos.com/forums/showthread.php?t=213689&highlight=Paint+code+resource
Other red names and color codes offered on Broncos:
Poppy Red* (S) 66,67 (same Ford 1730 Basic PN as Vermilion, AKA Calypso Coral)
Royal Maroon (B) 69, 70 [FoMoCo Maroon Basic PN 3059]
Rangoon Red (J) 66,67,68 [FoMoCo Basic PN 1515]
Signal Flare Red (Z) 68 [FoMoCo Basic PN 2025]
Candy Apple Red (T) 69, 70, 71, 72, 73, 74, 75, 76, 77 [FoMoCo Basic PN 2008]
Regis Red* (4) 71 [FoMoCo Dark Rd Ford Basic PN 3426)
Royal Maroon* (2) 73 [FoMoCo Maroon Basic PN 3059]
Viking Red* (6) 75 [FoMoCo Bright Red Basic PN 3560]
Cayan Red* (2) 76 [FoMoCo Tangerine Basic PN 5459]
Castillo Red* (K) 76, 77 [FoMoCo Bright Red Basic PN 5440]
*Indicates FoMoCo Promotional Name