<!-- ko foreach: AllPens -->
    <label>
        <input type="checkbox" data-bind="checkedValue: code, checked: $parent.chosenItems" />

        <span data-bind="text: name"></span>
    </label>
  <!-- /ko -->

{ code: "001" , name: "Parker"},
{ code: "002" , name: "Sheaffer"},
{ code: "003" , name: "Mont Blanc"}

"Pens": [{
     "PenType": "001",
     "Order": false
  },
  {
     "PenType": "002",
     "Order": true
  }]

self.checkedPens = function (pen) {
  if (pen.penType !== null) {
      self.Pens.push({ PenType: pen.penType, Order: (pen.order === "true") });
  }
};

self.checkedPens = function(pen) {
    var isChecked = pen.order === "true";
    if (pen.penType !== null && isChecked) {
        self.Pens.push({
            PenType: pen.penType,
            Order: isChecked
        });
    }
};