Hulk 340 came out before Marvel was computer-coloring, so any reprint or digital edition would have been recolored (as I'm sure the original printing plates haven't survived). If they also had to scan a printed book for the linework (which is likely, if there aren't digital files avaialble), it could be that the detail in the area that is now "glistening" was hard to clean up, so dropping it out as they did was easier. I worked at a computer coloring place that re-colored some old Classics Illustrated books back in the 90s, and the process was rather tedious.
I realized for the first time that this cover features something one does not normally see on covers; the tongues of two major characters, and neither one of them is Venom.