This would work:
var c = epaper.othermakemodel.is(':checked');
$("#dcolor")["insert" + (c ? "After" : "Before")](c ? "#lmodel" : "#otherlabeldiv");
Or even a one-liner:
$("#dcolor")["insert" + (epaper.othermakemodel.is(':checked') ? "After" : "Before")](epaper.othermakemodel.is(':checked') ? "#lmodel" : "#otherlabeldiv");
However, that's just using the ternary operator for the sake of using the operator.
Keep your code short, but more importantly, keep your code readable:
var element = $("#dcolor");
if(epaper.othermakemodel.is(':checked')){
element.insertAfter("#lmodel");
}else{
element.insertBefore("#otherlabeldiv");
}
This will save everyone involved a headache if you have to maintain your code a year from now.