Give them what they want, not what they ask for...
Whenever you're in doubt ask the doc. Now if you were to take the tooth number being restored, or the arch it's on th and C3 in the respective zones.en you can deduce the upper and lower portion of the teeth.
Not your fault for not understanding however, just shows how dentistry has evolved. Some docs won't write out the script much less draw a diagram. Leaves a lot of room for error in the translation and the lab is usually left holdin.
Call the doc and mention the use of a hand drawn pic at minium.Good luck
Forgot; from a technical standpoint if it's a pfm use the corresponding opaques and porcelains in the respective zones. Make sure you blend the transition zones in the opaque and porcelain layers respectively. Zr? then core=C3, and build with C4 and C3 in the respective zones.