I was looking for small SMD low voltage noise transistors today in AOE3 and came across the ZXTP2027FTA / ZXTN2018FTA that have the marking "951" / "851" on the sot-23.
I take that as a hint that they are really the same chips as FZT851... in SOT-223 and the thinned TO-92.
The spice results that I got were too good to be true, for all of the family, btw.
cheers, Gerhard