How are cloud bases and tops reported on PIREPS? Let's say I read a PIREP as follows...

KATL UA/OV KATL/TM 1522/FL080/TP C210/SK SCT013-TOP079/WX FV05SM
 HZ/TA M04/WV 24540KT/TB LGT/RM IN CLR.


I'm in KATL where the field elevation is 1,026, so if I were reading a METAR that reported bases at 013 I'd expect to enter the clouds at 2,300' MSL. I'm reading a PIREP here though, so based on this am I expecting to enter the bases as 1,300 MSL or 1,300 AGL? I have the same question with the tops.
It depends. For a PIREP cloud Heights are reported as they are read by the pilot. 

FAR AIM 7-1-16(b)


  ... In reports disseminated as PIREPs, height references are given the same as received from pilots, that is, above MSL.


This means some conditions may be reported MSL as read of the altimeter at local barometer settings while others may be set at standard pressure and read from there. I would assume that altitude reports less than 18,000ft are MSL.