Years ago California (CA) adapted their own emission standards that were higher then the Federal (FED) standards. New cars sold in CA needed to meet CA standards.
Over time many states adopted the CA standard as their own. These states don't call it their own states XX standard but refer to it as adopting the California emissions standard.
Not sure if PA adopted the standard, they have website below:
Emissions testing is also broken down by county or region. Testing is down to specific state and county/regional requirements.
Typically the emissions standards are set by year of manufacturer. Thus a car built in XXXX needs to pass the standard for that year regardless of make or model. Or it could be model specific.
I would check with your states emissions department and ask if they test by make/model/engine model/emissions stardard built to such a CA or FED.
Thus a car built to CA standards would be tested to the CA standard in place at the time it was built.
Each model is certified to meet a standard set by CA or the FED's.
By year built. In this case a car built to CA standards my have lower emissions but the location car and thus required test only cares that it meets the minimal emissions standard it has set. Typically this is by year of manufacturer.
Thus for year 1999, the standard is xxx, for year 2000 the standard is xxxy, etc.
Most likely this is the Federal standard for that year.
Some states just do an emissions test, others inspect the car emissions system for tampering or non-complient parts.
It is illegal under Federal law to tamper with the cars emissions sytem. Thus if this car is inspected it must keep its original emissions equipment setup.
Some states have no inspections and even through it is illegal to remove the equipment if the car is never inspected who would know.
Typically CA emissions standard cars have differant computer, converter, A/F sensor(s), distributor, maybe a differant cylinder head, cams.
One way to tell what changes were made is to shop for parts. If a part is listed by California (CA), Federal (FED), not for use on California, etc this means there is a differance between parts used.
Under Federal law, a good portion of the emissions equipment has a mandated warranty. Not sure what this is now, the owners manual or emissions warranty book that came with car should have.
For the computer and converter this used to be 8 yr/80K miles. Thus if one of these items fails even if the car is out of the manufacturers warranty, Toyota must replace the part(s) under the Federal mandated warranty.
Where you may run into problem is if there is a major differance between your area and California testing standards. It appears you state has an ODBII test where the cars computer is plugged into the testing station. If any trouble codes have been tripped or are pending, etc. the car will not pass.
You would be required to repair the car and being a California emissions certified may need to use the same type of part as on the CA certified car. This does not mean a Toyota part, but one that meets CA emissions standards. Typically but not always these parts are more expensive.
Much depends on the part. If the cars computer is looking for a California part having certain operational characterists and does not find it, a code may be tripped. The computer is specific to FED or CA emissions.
California cars are now very common, would not let this stop you from buying the car. But keep all of the above in mind. The CA emissions parts should last as long as the FED parts but if needing replacement a CA part may be needed.