“What is the basis of the dispute between the Rosh and the Rambam?” asked Yaakov.
“There are a number of explanations,” answered Rabbi Dayan. “The GR”A [260:24; 262:22] relates this to a general dispute between them about taking monetary possession in questionable cases. According to the Rambam, once a person takes possession, the burden of the proof now shifts to the plaintiff (hamotzi meichaveiro alav ha’reaya), so that the finder does not have to publicize the item. However, according to the Rosh, once the doubt arose, subsequent questionable possession is invalid, so that the mitzvah of hashava aviedah still requires publicizing the item.”
“Who is the halacha like?” asked Yaakov.
“The Shulchan Aruch [C.M. 262:12; 260:7,9] cites the Rambam,” replied Rabbi Dayan. “Rama, however, argues in the final case of safek hinuach that one needs to publicize the item if it has a siman. Most authorities assume that one does need to publicize the coins even in a case of doubt.” (Hashavas Aveidah K’halacha 1:12)