Kodak Ektachrome Slide (regular slide)
It has a slight ripple on its surface.
Kodachrome is Kodak's brand name, but the slide mount (frame) doesn't always read "Kodak" or "Kodachrome".
The way to determine if the slide is Kodachrome is to look closely at the film surface. One side of the film is duller than the other. Other ways to determine the dull side are:
You need to look closely at the dull side. You can tell its Kodachrome because it has a much more distinguished texture on its surface. Regular slides have a slight ripple on its surface. See a close-up photo of a regular slide and 2 close-up photos of Kodachrome slides below.
Click to enlarge.
Kodak Kodachrome Slide
It has a texture on its surface.
Generic Kodachrome Slide
It has a texture on its surface.
Click to enlarge.
Click to enlarge.