Short answer: No
Basic stroke attack should be a (more "vertical" than "horizontal" - to use your terms) "push through"
the string being played (with the first knuckle breaking to release tension, thus allowing the finger to move on to rest on the next string) rather than a "grabbing pluck"
of the string. Consider how a harpsichord's quill attacks a string.
There are, of course, other strokes and occasions when you may want to use a "grabbing pluck"
attack in which the first knuckle will remain tensed.
Your best bet is to find a good teacher who 1) plays very very
well - 2) has good knowledge of music (not just rock and roll or blues progressions etc.) - 3) understands the physics of the instrument and 4) understands how the human hand works.
(read: "most certainly will") vary