Probably more interesting as militaria than movie memorabilia (how many people ever heard of this old Rock Hudson/George Peppard movie?).
The movie has nothing to do with the Siege of Tobruk, but is about the Long Range Desert Group trying to blow up fuel bunkers during the North African desert campaign.
The uniform is Western Costume Company, but surprisingly the attachments seem to be genuine WW2 issue. Buttons are SS, painted DAK (Deutsche Afrika Korps) khaki-grey. Epaulettes and tabs appear genuine, but stitched incorrectly. The DAK cuff band and breast eagle are stitched correctly (pre 1939) but are in unusual colors.