Well this is pretty easy to test. Use a wide-gamut display and use the display's profile. Yeah, sure that might not be accurate, but it tells color-managed applications what the display color space roughly is. Then play a video. Observe whether the colors are drastically different from no profile and sRGB emulation in the display. In a color managed system, both of these should look roughly the same (and they do).

My result: Yes, they are. Totally different. Crab people everywhere. Player does not matter.