while it might be grammatically possible to write it with or without the and, FFG consistently used 'in arc at Range' when discussing attack range, So they most definetly have different meanings in this discussion.
Look at E'tahn Abatt:
"When an enemy ship inside your firing arc at Range 1-3 is defending, the attacker may change 1 of its [HIT] results to a [CRIT] result."
That ability uses the phrase you claim has special meaning in a way that has nothing to do with attack range.
Edited by WWHSD