No. You need a bigger head in relationship to the thread for drywall as well as a flat head when installed . Floating shelves require a bracket to anchor steel to wood and you would also want a bigger head
screw length from bottom of pan head is 1". it's a #6 (#7 ?) screw. head is 19/64" diam. I'm finding lately that (all screws) vary slightly in screw size; that is a #6 might actually be a bit undersized or over-sized! quality control & standardization isn't what it used to be.
look on Home Depots website for location.
You'll have to ask a clerk when you arrive at the store.
what types? they are all 1" sq drive as described on pkging.