This sort of thing can get complicated .
One way to check things out would be to get hold of a original track pin in good condition , or better a NOS pin and do a surface hardness test on it . The TAFE I went to had a hardness tester in the workshop . Basically , the tester drops a pointed weight onto the test piece and a scale records the depth of the imprint , something along those lines
The original pins may have been surface hardened mild steel ? Somewhat like many gears are in gearboxes.
http://en.wikipedia.org/wiki/Case_hardening