There is not much to compare, the RayDAT is a fully digital working card.

You detected already the major change, with the availability of FS clock, various RME products got an overhaul in terms of clock chip. Even higher jitter reduction. As the manual tells, the signal processed by SteadyClock is of course not only used internally, but is also available to all outputs of the HDSPe RayDAT.

It's possible that a newer version of FPGA (Spartan chip) had to be used because older versions are not available any more.
The Release notes in the driver ZIP archive sometimes list HW changes, nothing found regarding this.
But even if … there is no change for the product itself. I remember another thread where RME confirmed, that this has no impact on performance in any way. It's simply another FPGA (programmable CPU) running the firmware.

May I ask what is the actual reason for your request, perhaps there is something else that could be assisted with.