Got it figured out.
To eliminate the timestamp from exported orders.
Replaced this:
$str_export .= $FIELDSEPARATOR . $FIELDSTART . $order_details->fields['date_purchased'] . $FIELDEND;
With this.
$str_export .= $FIELDSEPARATOR . $FIELDSTART . zen_date_short($order_details->fields['date_purchased']) . $FIELDEND;

On the date display I had to move the date_purchased from the end of the query to the appropriate position in this code as I am not displaying all the fields.

$query = "SELECT o.orders_id, customers_email_address, delivery_name, delivery_company, delivery_street_address, delivery_suburb, delivery_city, delivery_postcode, delivery_state, delivery_country, date_purchased, shipping_method, customers_telephone, order_total
FROM ". TABLE_ORDERS ." o
WHERE downloaded_ship='no'
ORDER BY orders_id ASC";