(archer fingers, thumb behind neck)
Yes. And a huge NO. Thing is, having had a few "classical guitar" "lessons" in my youth (no other tuition) I am still hampered by exactly that. So, when I tried to do the Guns and Roses "Sweet child of mine" thing, I found myself trying to plonk each note with a nicely curved, thumb behind neck, correct style, separate finger. Yeah.
Needless to say, guitar playing does not work like this, referring to the "Scuttle Bug" challenge. Now try that fingerstyle. Hmm, there's a real challenge for you guys... Video of your fingers. Thumb behind neck, fingers curved, no double string fretting, etc. The "purists" see this as the only real guitar playing. Me? I try to remember the difference between "A", "C" , "D" and "E" chords on the first few frets...