Not sure exactly - are you talking about the commerically manufactured Steyr-Mannlicher "L" or "M" series of hunting rifles? The ones made prior to the current "SBS" series?
I've got a 1970's (?) era Steyr Mannlicher "M". It's a wonderful rifle, but I worry that the quirky plastic Mannlicher rotary magazine might break on me someday, leaving me with a very expensive single-shot rifle (replacements seem to be unavailable)
I looked over my rifle's QD scope mounts and, aside from the word "AUSTRIA", they are unmarked. I'm guessing they're original Steyr mounts.
Leupold markets 2-piece, QD scope mounts for "Steyr Mannlicher" (Midway part number 656-287) but these may NOT be compatable with older Steyr Mannlichers.
Wish I could help more - sorry.
This discussion board (Steyr Club) is very handgun-oriented. You might try asking over at "Steyrforums" as they emphasize the Steyr Mannlicher rifles instead:
http://steyrforums.com/