Email them or call and ask.  It's been my experience they will sell them for support reasons when they have the parts.   For example getting a S3 one at this point is slim.  But one they still make such as a S5 much better chance they will have the part to sell.

I once bought a S3 board when they were still new.  I lost power and it ofcourse bricked it, and I did not have parts to flash it.