Being that the 2600 was released after the 7000, I would think that the 2600 would be able to play any style that the 7000 can.
I'm not sure if the "sounds' would be exactly the same on both however.

Usually compatible Technic keyboards search and try to substitute sounds as close as possible as to what was intended.If for an example the Americana disk used a rotor organ in one of their styles, and the 2600 does not have that exact rotor organ sound, it will substitute the closest matching sound.

So, as far as I know, they should work, although they may sound slightly different.
I would certainly double check with whoever you intend to purchace from before shelling out any money.

Larry Hawk