The subject bicycle has what appears to be the Extra version of the Valentino rear derailleur. Assuming it is OEM would make this model no earlier than 1969. The brakes are Universal Model 58. It is a bit curious that the newer Universal Model 68 is not used but the Model 58 were still available through the 1970s. The cottered Nervar Sport crank with integral spider is boom era. Components point to a boom era Rekord variant.
The decals are consistent with early boom era and from my current understanding of the Bianchi serial number format and locations, it should be a 1972 model manufactured in late 1971. Consequently, it is almost certainly a Rekord 72.
Please note that components vary from the referenced Rekord 72 on the Classic Lightweights UK site because that bicycle has been misidentified and/or had the components updated. Its Campagnolo Nuovo Gran Sport components did not come out until 1974.
FYI, the referenced Bianchi catalogue is from 1974, not 1973. It pictures Felice Gimondi in the World Champion jersey, which he won September 02, 1973 in the professional road race of the Barcelona World Championships. Consequently, the picture was taken sometime after this date, when Gimondi was the reigning 1973/1974 World Champion. That would make it a 1974 catalogue and is corroborated by the inclusion of a Rekord 74 model.