I kind of think one doesn't even need to train rear delts if doing plenty of back work. You don't even need to feel it to work it, so to speak. If the muscle is loaded increasingly it will grow regardless if you "concentrate" on "back" only. How common is it to have great lats but no rear delts? If someone is like this adding specific rear delt movements will most likely not do much. Now I've done shitload of rear delts anyway...
Now I saw some discussion on IG, which I can't ffind now, where some expert claimed rear delts can be seen from the front in good bodybuilders. I didn't quite get it..
Then there was a kind of a sematic quibble. Guy said rear delts are the real medial delts. "Medial to the body." Lol.
I've said it before, the most important thing for rear delts or the whole delts is androgens, not training. Same as with traps, these are simply not seen much in naturals. You can especially see the androgenic rear delts in otherwise small fitness girls, there is this "unnatural" lump or knot there Lol. This is a pretty good "natural or not" sign. It's interesting how androgens cause this, what looks like, clavicle widening. It's not but it's another reliable androgen use sign, if someones "shoulders" suddenly widen.