Panerai will often include the name of the main model on the dial of the watch. So your first step in finding out what Panerai Replica you have is to check if there’s a name on the dial.
Panerai Radiomir Fake watches do not have any crown guards around the winding crown. The standard Radiomirs include a conical winding crown and thin wire lugs while the Radiomir 1940 models have a cylindrical winding crown and thicker lugs.
The newest type of Luminor to join Panerai’s collection is the Luminor Due, which made its debut in 2016. Like the Luminor 1950 copy watches, the crown guards of the Luminor Due are also marked with “REG T.M.” engravings; however, the cases of the Luminor Due are notably slimmer than those of the other Luminor models.
In summary, the quickest way to tell what Panerai model you have is to remember that Radiomir watches have no crown guards, Best Luminor Replica watches have large semi-circular crown guards, Submersible watches have rotating dive bezels, and Mare Nostrum watches have round cases with chronograph pushers.