C. Sicinius in Diod. almost certainly refers to the same person as Livy's Siccius. See 493, Tribunes of the Plebs. (Broughton MRR I)
Diod. (11.68.7) and Piso (in Liv. 2.58.2) agree on four names to which Piso adds Mecilius as a fifth. Duillius and Siccius prosecuted Ap. Claudius, Consul 471, who died before the proceedings ended (Liv. 2.61.1-9; Dion. Hal. 9.52.1-54.6). Note, however that according to Fast. Cap. he became Consul in 451 and Decemvir in 451 and 450. (Broughton MRR I)
Tr. pl. 470. See MRR 1.31. Note that J.-C. Richard, Origines de la plebe romaine 529, prefers Sicinius, the reading of Diodorus and the properly plebeian name; cf. Ogilvie, Comm. Liv. 382. See T. Sicinius (13). Cos. 487.
(Broughton MRR III)