This is the bottom stamp of a vertical on strip of 10 x 60 sen stamps.
It only indicates that the strip is worth RM6 for the postal clerk's
accounting. The next vertical strip would have RM12 as the value of 2
vertical strips - 20 x 60s stamps, etc.
Austria did issue black, imperforate black prints of various stamps. A
search shows that France International
(http://www.stampsbythemes.com/kall/tall0003.htm) is selling a right
vertical pair of your stamps at US$60, calling them privately
perforate...