Some guys that have had success at other weights that have competed at 65kg: Zain Retherford (65kg no medals, 70kg 1 gold, 1 silver), Aliyev (65kg 1 silver, 61kg 3 gold, 57kg 1 bronze), Yazdani (65kg 1 silver, 70kg 1 silver), Niyazbekov (65kg 1 silver, 55kg 1 bronze), Chakaev (65kg 1 bronze, 61kg bronze), Rashidov (65kg 1 gold, 61 kg 2 silver), Chamizo (65kg 1 bronze, 1 70kg gold, 1 74kg silver), James Green (65kg no medals, 70kg 1 silver, 1 bronze), Gadzhiev (65kg 1 silver, 70kg 1 gold, 1 bronze), Iakobishvili (65kg 1 gold, 70kg 3 bronze), Logan Stieber (65kg no medals, 61kg 1 gold).
It is a mixed bag as to whether they performed better or worse at 65kg compared to other weights. That being said, many of athletes that have competed at 65kg have had success at other weights.