If you mean "residues that are in the amber parm file and thus don't  
require running antechamber"  I don't know of a command-line specifier  
for exactly that, although the above may work in many cases.

If you do "addcharge standard" which adds charges to the residues that Amber has in its parameter files, then "sel :/amberName" will select those residues only.  The addcharge command (and Add Charge tool) adds the amberName residue attribute as the name used by Amber for that residue (e.g. CYN for N-terminal cysteine).

--Eric