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Since the only stampings I see are the number "46" on the LH side of the receiver ring & bbl, and on the nosecap, and the manufacturer's crest marking atop the receiver ring (the Budapest, Hungary arsenal), I would have to WAG that "46" is the rifle's SN - typically stamped on most Euro military rifle's parts.
You can find out more here:
http://www.hungariae.com/Mann95.htm
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