SNA dates, actual manufacture date, and order of production|Winchester Rifles|Forum|Winchester Collector

Here is an interesting rifle which brings up a fair amount of confusion regarding these topics.  It is a Model 92 sporting rifle, with octagon barrel in 25-20 caliber.  The serial number is 846008 which by the SNA dates corresponds to 1918 production.  BUT… the upper tang is clearly stamped “MODEL   92” which came into use in 1920 by SNA dates. 

My questions are:

1.  Was the receiver manufactured and serialized in sequence in1918 without the tang being stamped?  or

2. Was the receiver manufactured between 1920 to 1927 (the period of use for the number 5 tang stamp use) and then an earlier “unused” SN applied to the receiver?  

There are over a dozen other similarly marked rifles in 1918 with random, non sequential serial numbers.

Michael