I am not saying always David but my experience is you can, and I won't listen to anybody no matter how eminent who say's you can't.
Surely, how one appears in death, is dependent, to a degree, on how one died. My adored late partner didn't look any different from how he'd looked when he fell asleep on the settee. However, he'd been terminally ill, and when 'help' was offered, he'd accepted.
Now, if we look at the expressions of both June and Sheila, to me, there's no perceptible difference, yet we're asked to believe that Sheila chose death, and June had death, terrifyingly and torturously, inflicted on her. Take away the evidence of their injuries
and I don't believe it's possible to know, from their expressions, what horrors either were subjected of prior to dying.