No, the data did not change.
I have a server with 16 SAS drives, some were already populated with data and setup in raid 1 arrays, and others had not even been populated with data yet. I took each drive and pulled it from its hot-swap bay and plugged it into a bay on another server, that was setup as an IDE SATA port, and ran the program on it. Then after I was done running SDPARM, I replaced the drive back into its original location (some were part of RAID 1 arrays and others were not) and if it needed to reestablish the array it would rebuild otherwise not.