I would say smoky black isn't always smoky, but very often is - to me it just looks a little bit different from a completely black, just a bit washed off looking - and yes some are 'on the border' and really look like other colors. But most of the time, the smoky black - to me, honestly, yes, it just looks somewhat 'smoky'. Not like a cream or Weimereiner color, but just a bit 'washed off'. For me the real tip off it's a smoky black is that the mane and tail color is very close to the body color. We almost bought an Icelandic of that color.
And actually, it is extremely rare that a black does not fade in sun - new research in color has shown that.
There now is a genetic test to differentiate black and bay from brown, so if you really are interested in seeing what your horse's color is based on its genes, you can do that.
There are other ways to tell what genes an animal actually has for color, for example, test breedings.