Then I saw the Rambam writes in Hilchot Gezelah va'Avedah 14:5
When the owner of an article does not know of its loss, he is not considered to have despaired of its recovery, even if it does not have a mark by which it can be identified.
What is implied? If a person dropped a dinar and did not realize that he dropped it, he is not considered to have despaired of its recovery until he becomes aware that he dropped it. Even though he will certainly despair of its recovery when he realizes that he dropped it it is forbidden to take the article until that time.
This is linked to the famous dispute between Abaye and Rava regarding yiush shelo midaat and I understand the conclusion of the gemara in Baba Metzia 22b to be that one cannot take something that the owner has not yet despaired of finding.
But when an object doesn't have signs, the owner despairs right away. And money, unless in large quantities or set up in specific shape, does not have signs. The dinar mentioned by the Rambam seems to belong to money without signs.
So this Rambam appears to go against the halacha that one can take normal amounts of money found in the street (as I think the Shulchan Aruch agrees to in CM 262:3).
How should I understand this Rambam?