I believe its the same. The point of bleeding the salmon is to not let the blood spoil any meat. I would assume the same for a trout, although a much smaller amount. Gutting is the same. Gills and organs out and gone! Bonking merely stuns them, unless you really give em a good whack right on the brain, it very well may kill them. On trout again, smaller scale. On a Salmon, you give a good shot to the head, and you can see their eye roll from a downward position to looking straight out in the middle. At the point, you want the heart still beating so you can throughly bleed it (bleed it in the water too, that way the blood does not coagulate and clot up, but freely flows out)
As far as the flopping. If it is actively moving and flopping numerous times, I would be sad for making him suffer. One flip of the body I would consider simply a muscle reaction. I am not all knowing here at all, but this is what Ive picked up. But I did have one pink that was bonked, then once more JUST TO BE SURE, then slit open, gills removed, and FLIP! A solid 30 seconds after bleeding. Scared the crap out of me. Again though, if the eyes are right in the middle of the socket, he is done.