need help with case tang stamp ID

[wudnme]

picked up this little nugget at a local antique shop for 18 bucks. I wasn't sure about the stamp on one blade ,but I bought it anyway. It is a 6201 with an R under it. there is one x under the USA. on the small blade there is "BK" stamped twice on the same side. I am aware that it is a model 6201 from I believe 1979. Not sure about the R or the BK stamps indicate.
http://www.putfile.com/pic.php?img=6169683
http://www.putfile.com/pic.php?img=6169684
http://www.putfile.com/pic.php?img=6169685

 

[Nukemkb]

The R means either a bail in the handle or a razor blade...

 

[knifeaholic]

That is a 6201RSS, part of what Case called the "Gentleman's Line", introduced in 1978 and made for a few years.

The BK looks like it is not factory, maybe someone's initials added by a jeweler.