Correct, when boosting from tractored it's only using the 1 straight template. You cannot boost with the banks with tractored.
However it's worth noting, when you barrel roll with tractored, if the ship you're moving is a StarViper then i0t must use the starviper's special barrel roll rules (barrel roll with 1 banks instead of 1 straight). StarVipers are crazy ships. :D
If another ship had boost rules worded just like the Starviper's barrel roll rules (e.g. "when you boost, you must use left turn and right turn templates"), that would most likely apply to being tractored. But I can't think of any that work quite that way, and FFG has never added clarification for any except the StarViper, so I don't think there's any like that currently.