I came across a pic of the actual plane, clearly indicating that walk lines were not used. Airfix had this correct, yours truly thought that walk lines HAD to exist, otherwise what is the use of "WAKLKWAY - DO NOT WALK" stenciling?
Well, interestingly "WALKWAY - DO NOT WALK" stencils were used, but no lines: those were applied only at the export Vipers of that time, whereas they were seemingly adopted also by US Air Forces later on! As our friend @j-healy stated, there's a lot more to the F-16 than we might think there is!
To make a long story short, I carefully removed the walk lines (yes, by using water and my nails...) from the Desert Viper, with only the "WALKWAY DO NOT WALK" stenciling destroyed; thankfully, a leftover decal sheet from a same build saved the day!
Here is the Viper sans the walk lines:
Thanks for stopping by!