kscessnadriver,
one would assume he's asking the question outside of any company's OpSpecs. which would relieve him/her of the reg.
for example: if one got their PPL ASEL license in a C152, one would be able to LOG all time as PIC in a C172RG "as sole manipulator of the controls" or any ASEL under 12.500 pounds (or needing a type rating, etc).
in order to ACT as a PIC, one would need an endorsement in said cat/class if they were without an instructor onboard, etc.