There are a number of firearms charges -- improper display of a firearm, possession of a firearm by a convicted felon, possession of a firearm during the commission of a crime, possession of a concealed firearm, aggravated assault with a firearm, etc.
For an arrest to be made by the police, they have to have probable cause to believe that a person indeed committed a crime.
In Florida, witness testimony can be used as substantive evidence in Florida. Police can come to the conclusion that they have probable cause to make an arrest based solely on witness testimony, even with no physical evidence.
If the police wants to obtain an Arrest Warrant, they would have to file a sworn affidavit with a Judge describing how they came to have probable cause. The Judge would then decide whether or not there is probable cause that the individual committed the crime alleged. It is possible for a Judge to decide that there is probable cause based solely on witness testimony, even with no physical evidence.
Simply, yes you can be charged with possession of a firearm so long as a person is willing to testify under oath that they saw you with a firearm in your hands.
There is no requirement that law enforcement conduct a residue check or even find a gun. That goes to the weight of the evidence presented by the State and whether they have convinced a jury beyond a reasonable doubt.