software-RTC adapting the AVR-swRTC to SAMD21

Well I guess I can boil down my question to

does the swRTC.h-library -function

swRTC::getTimestamp(int yearT)

return the exact same timeformat as

the RTCZero.h-library-function

uint32_t RTCZero::getEpoch()

if not:
what conversion(s) do I have to do to transform the return-value of
uint32_t RTCZero::getEpoch()
into the same time-format like the swRTC-library-function swRTC.h ?

best regards Stefan