In theory and for the 99.9% of cases yes, but I believe this also depends on facing. In a random mission, without being sensor locked, I was under LRM fire although I didn't have LoS to any enemy Mech or vehicle. But they, obviously, were seing me. Due to the 'Mech receiving the fire, its location (near the edge of a mountain, close to a vehicle which was sligthly higher than the Mech, and the facing of my Mech (not straight to the vehicle, quite sideways), I developed the theory that, under some fringe cases, one team can have LoS while the other does not, wether it's happening something similar or it was a glitch/bug, I have no idea. But I'm 100% positive about not being sensor locked, I checked the Mech and didn't have the tag.
Well, although I usually also like to acquire as much evasion pips as possible, RNG happens... and my Vindicator almost got shredded after two attacks form afar, first one with 5 or 6 evasion pips, the second one with one less. I know the numbers won't be as high as -82.5%, but still, they hit the poor Vindi with almost everything they shot...
PS: I'm afraid this post looks like I'm an as#o&e that only wants to say the opposite of other people... it's not the case, I just want to point that, sometimes (either strange situation of LoS or due to RNG), things doesn't go as theory/numbers say, which is part of the charm of this game