Iwc tang buckle

Hi.
I have located an old stainless steel iwc tang buckle that looks legit. However there are no stamps or anything else on the back. Are they supposed to be like that?

[](s1033.photobucket.com/user/RyanK_2010/media/received_10155623187528571_zpsqhklwpje.jpeg.html)
[](s1033.photobucket.com/user/RyanK_2010/media/received_10155623187788571_zpszd8aruxw.jpeg.html)

Buckle is original. Not all buckles had manufacturer markings.

Thank you. Much appreciated.