Ok first off, there are no historically accurate reproduction sabers currently available and certainly none with any sort of temper to the steel.
A saber is not a sword, there is a difference. Swords are for cutting while sabers are for cleaving. As such you will not find any sharpened to a razor's edge. Original examples can and are routinely found with a edge ground onto the blade in the field. There is also anecdotal evidence of troopers doing exactly this found in their reports, letters home and regimental histories.
Historically, sabers were issued to every mounted cavalry trooper in Federal service and a large number in Confederate service. They were used in cavalry vs cavalry combat and the Federals actually became quite well know for their saber use. There are also a good number of casualty reports throughout the war that list details of saber wounds. It is a weapon meant for use from horseback and not from the ground.
I personally own an original German made M1840 with a field applied edge and a Roby M1860 with only the last 8 inches of the blade "sharpened".
Dave