They are constructed the same. That said, Nosler and all companies frequently change the construction of bullets, such as jacket thickness, etc. I've found these fly and perform exactly like the BTs. Advantages of the BTs are no point deformations, potential ballistic advantages due to the more streamlined shape. I do know that the .284 120 grain Ballistic Tips of fairly recent manufacture have rather thick jackets, more so that earlier ones.
I'm an old fart that has a sizable cache of Solid Bases in many sizes (Am I a Hoarder?). These are great deer/antelope/sheep bullets. AND, I've found that every handload recipe with SBs can be used with BTs. The chronographed velocities are very close, too.
