i found a pelican 140 for about $80 us. how do i know if i am getting a 40s or 50's etc pen? the nib says 14c 585, and has the pelican logo on it. is this a semi flex nib or the ultra semi flex? how do i know how flexie this nib is by looking at a picture? the seller claims it is in perfect working order, i am on the fence with this purchase, can anyone help?