Monkeyleg, by all means get the real McCoy if you feel uncomfortable getting another hall transistor with a different part number. I can totally see where you are coming from with that idea.
I was just telling you that there is about a 95% probability that THIS application will work with ANY hall.
Of course I am not proposing you stick in a T-092 plain old transistor with a base connection! But any T-092 (I assume that is the shape you have - I did not look at your pix) HALL TRANSISTOR likely will work.
Yes, the phantom is very complex, highly computerized, but at the end of the day, the 3 hall transistors are ON or OFF - nothing inbetween. They either turn on and conduct 100% seeing a magnetic field, or they are turned off. Being so simple, anything that sees the magnetic field will likely work. That was my point.
As a side note, it is interesting to know why there are 10's of thousands of transistor part numbers.... Did you know that once a basic shape and size is designed, it comes off the same assembly line and then is GRADED in automatic equipment. Based on the alpha and beta gains, response BW, etc., a part number is assigned to it. So although one part is made over and over again, it is tested and then that same part is assigned one of 1000's of part numbers! For critical or some analog circuits, this testing saves designers lots of time by letting them now the part number they picked will work within a small range of gains and such. Most designers of analog circuits will use emitter resistors and bypass caps to allow a wide range of transistors to work anyway too. When I repair an audio radio or amp, it is often a matter of picking the right physical size device and double checking its voltage ratings and it just works.