1976 for 1977 abolished all non-metric distances except mile (marathon non-round in both)[4]
for 1963 field events official metric with imperial to nearest quarter-inch and rounded up [4]
hurdle heights and field event length and weights mix of metric and non (presume all now defined in metric; when did rounding-down of imperial measurements take effect?)
Boxing at the Olympics#Events: pre-WW2 used pounds even in metric countries. Who organised? Check official reports. Weight class (boxing)#Amateur boxing: "When the AIBA was founded in 1946 to govern amateur boxing, it metricated the weight class limits by rounding the pounds values to the nearest kilogram."
Swimming: "FINA ruled in 1956 that starting 1 Jan 1957 they would only recognize metric marks made in 50 metre pool."[9] — does that mean wouldn't recognise yard marks, or wouldn't recognise metric marks set in non-50 metre pools?