I recall a gemarah (possibly Yerushalmi Taanit?) wherein Rebbi Akiva is quoted as proclaiming that Shimon bar Kosiba was the king Moshiach. I further understand that this statement could be one of belief as opposed to halacha or fact. I would like to know if there is any restriction for someone to publicly proclaim whether as belief or fact, that another person is the messiah.
The Reason that the Rambam writes laws about it is in order to know who Moshiach is during the time of exile (since after MOSHIACH comes it will be obvious who he is)
To answer your question simply- if he fits the Rambams Specifications Then yes you could say he is chezkas Moshiach