Laos 1962 1 Kip Color Questions

The colour trial P8ct has signature 3 combo (which is the same signatures seen in your first "UNC" example). That means it cannot be your 2nd circulated note which bears the Signature 4 combination.

My SCWPM states that P8 is "brown on pink and blue underprint." It is more likely that the second note, which appear to have more blue" has been either washed or processed in such a way that the red has either worn out or bled out of the design (in the note where you see more blue) since it has been circulated. Even exposure to strong light (or sunlight) can diminish some colours more than others. (one of the reasons it's not such a great idea to mount/display a rare banknote)