Yes the break periods apply to all drivers of CMV's including package drivers. If you have a DOT number on the side of your vehicle, it's a commercial motor vehicle (and the definitions have been posted
ad nauseum on here). A Commercial Drivers License is only required for certain classes of CMV's. Package drivers may not be legally required to have a medical certificate if they drive in an "exempt intracity zone" but this does not mean they are not driver of commercial vehicles and not subject to the HOS regulations.
Physical qualifications for drivers. - Federal Motor Carrier Safety Administration
Limited exemptions for intra-city zone drivers. - Federal Motor Carrier Safety Administration
Note that in 2014 CDL holders no longer have to carry the certificate on their person which will be a nice change.
The 30 minute rest period & 1-5 am restart periods apply to all drivers of commercial motor vehicles. Package cars are involved in interstate commerce and therefore subject to the Federal regulations. Some might remember when your DOT number was an ICC number (Interstate Commerce Commission). Again, Package drivers have different regulations governing the required documentation (i.e. logbooks) than CDL drivers, but they are subject to the same regulations as far as the HOS goes.
What is legal and what is enforced in any given area can be two very different things. DOT Enforcement officers are the same as local Police in that they all have their own focus and list of things they let slide. In my State independent and foreign drivers are pretty much guaranteed to be stopped & given the full anal inspection while fleet carriers seem to get a pass unless they do something to get the officers attention. An enforcement officer does not need probable cause to stop any commercial vehicle at any time for any reason.