Well, the film stock is usually identified on the very edge of the film, outside of the sprocket holes. If it's a Kodak print, there's a date code and then the type of stock is identified. If it's LPP, it will say "LPP".
LPP (Lowfade Positive Print) was a very low fade stock introduced by Kodak in the early 80s. I've seen 30 year old LPP prints that still retain all their original color.