Yep, that's quite possible. The sympathy vote alone would've been hard for opponents (primary and general) to overcome.
I await Caro’s last volume on LBJ. There should be some interesting tales about the LBJ/RFK dynamic. Recall, too, that LBJ and Hoover were old drinking buddies and you know that pi$$ed off RFK, since he was nominally Hoover’s boss as Attorney General.