Hiya Ikor
This is indeed a topic that concerns quite a few M and S Series owners. At this time, there are no Steyr factory triangular trapezoid night sights available...not yet. <shrug> There are factory Tritium night sights available through Steyrarms. Here's the link.
http://www.steyrarms.com/index.php?id=40
Also, PT Nightsights have their own night sights available and will install for free. Contact Jerrie Ling and I believe there is a discount for Steyrclub members. Here's their websight.
http://www.ptnightsights.com/
There is talk of Steyr having plans on the drawing board at present for tri-trap nightsights, however, that has yet to be confirmed. There are other aftermarket sight companies working their way over to the Steyrs, but for now, they have not included the M and S Series offering that there is not enough interest to make the sights economically viable. Lame bastards! :evil: Anyway, that's what I know, in a nutshell. <shrug> There may be other members with more information and I encourage them to step forward and volunteer pertinant info on this subject. I'm hoping that they will have some good news to offer.

Anyway, tell your buddy to enjoy one of the finest shooting handguns ever, IMHO.
Wulf <-- M357-A1 shooter. 8)