I found the answer. The sheath, lol!
The difference between the BK2 and BK22 is the sheath. The BK22 is the same knife but outfitted with a polyester sheath which does have a velcro pocket to put either a small stone or a Firestarter (flint and steel) which is what I do. ... I do like the BK22 sheath as it can be easiliy attached to a molle pack.
The grip scales also look different.