Aren't those orange drops BoP anyway? I soloed Hammer Station and Esseles a few times for lightside points and all the stuff the bosses dropped was BoP.
But yeah, they seemed very much based on my class. And on my Smuggler, in two normal Esseles runs with another human player, I got two orange blasters, two orange jackets and two Esseles gloves... it was a little crazy. Wasn't complaining though.
On My Marauder, I ran TBT 4 times in a row with a BH and every single drop was AIM. I then soloed the first Droid boss after those three and my Marauder's Vest dropped.....
It may be random, but the classes present have to effect the RNG in some way. Maybe giving an extra % to the roll based off the classes in the group or something.