In a word no. Even as early as 1848 there were strong calls for the unification of Croatia and Dalmatia. The Dalmatian Language was predicted to have 50,000 or so speakers in 10th century. By the 1400's it was heavily influenced by Venetian and basically shrunk to some coastal settlements. Many of the speakers were in Northern Islands which weren't even part of Dalmatia. By the time of nationalism the province was majority Croatian and the Nationalism was all about uniting the two provinces.
An independent Dalmatia requires a POD sometime after the fall of Rome to be realistic. Unless you want some kind of Austria situation, but Croatia is small anyway and so that's unacceptable.
Actually even earlier. The first newspapers in Croatian language were printed in Dalmatia in 1806.
To have a non Croatian Dalmatia you would need a POD during the 7th century or different approach by the Venetians during the 18th century.
The first census that determmins ethnic compostion in Dalmatia happened in 1850. determined 304,152 Croats (76.6%), 74,524 Serbs (18.9%) and 14,645 Italians (3.8%).
The only region of todays Croatia that might have developed into a separate ethnic group and a independent state is Slavonia. According to the 1840 census of Croatia and Slavonia there were 777,880 Croats (48%), 504,179 Serbs (32%) and 297,747 Šokci (19%). Šokci were concentrated in Požega, Virovitica and Syrmia county and in Slavonian Military Frontier. At the time these four districts had a total of 580,233 inhabitants making Šokci majority in the region. Today Šokci consider themselves Croats(some of the most nationalistic for the matter) but it is not beyond belief that under different circumstances they could have developed into an independent people with a nation state of their own.