I would think so, yes… .we use the TinyGPS library in the code. So in principle you could pull the time in the same place we pull the latitude / longitude, save it in a variable and use it in the printCsvDataLine (?) function. Or better might be to use it as the Sync provider for the Time lib.
I think there is an example of doing exactly that. Take a look at this, it should be useful: https://github.com/PaulStoffregen/Time/blob/master/examples/TimeGPS/TimeGPS.ino
Please can you let me know if you have success with this? I don’t really have the bandwidth available to integrate and test this code for you myself. And for Air Quality Egg in general, there are questions of priority to consider, if there is both an RTC and a GPS present…