Hardness Testing a Knife

[Mark Reich]

If I get a knife tested ( at the thickest part of the blade) does the included angle of the blade, even though it is very small, give results different than those of heat treated flat stock?

HERE is a very good overview of Rockwell testing guidelines and practices, including information on the perpendicularity of the indenter to the test surface. 

The problem with testing a finished blade is that the test will leave a huge stress riser. That little dent may not look like much, but it gives the blade a place and reason to break.