Hello Brian,
Pete Lesler (listmember) is very informative on these details. He sells these correct clamps in complete sets or individually. It seems that there are about fifty or sixty in all! Also I believe that your 69 280-SL should have mostly the later "Norma Style" screw type clamps. These are also different than the American style worm screw clamps which look out of place and can damage the hoses. Earlier W113 cars like the 230-SL had the earlier style clamps with the banding and the cotter pin type tightener.
Joe Alexander
Blacklick, Ohio