1. Possession of regulated firearms without the necessary licenses or permits shall be punished as follows:
1. With imprisonment for one to two years, if the firearms are handguns.
2. With imprisonment for six months to one year, if the firearms are long guns.
2. The offenses described in the preceding paragraph shall be punished, respectively, with imprisonment for two to three years and one to two years, when any of the following circumstances apply:
1. That the firearms lack manufacturer's marks or serial numbers, or that these have been altered or erased.
2. That they have been illegally introduced into Spanish territory.
3. That they have been modified, altering their original characteristics.