Well, now I'm confused...
I looked up various "definitive" data based for serial numbers, my rifle might or might not be one of three different models; Dates seem to point to 1953 regarding serial number, but 9.3 x 62 either were built with HVA actions or and not FN, or were not built that year. Rifles built that year had walnut stocks according to another source. More lost than what I was. LOL
Well, online sources on HVA firearms are sometimes foggy... that's why a long time ago, we built a database for the HVA firearms. We mostly go with the datas from the HVA museum, but even there, there are errors / omissions.
So, maybe to make things more complicated, here's how it goes for the 9.3X62 rifle production, and this is only for the 9.3x62 chambered rifles;
First there was the model 46AN, based on M38 receivers (227 made), then, the model 246 on the FN M98 military action (226 made) both having serial including a "N"
Then, the 649 line was introduced, first variation with M38 actions ( SN 90 001 to 92 859 in 1944-'47) then, for the second variation, they used FN M98 while they became the "commercial" actions, (SN 92 901 to 97 736 from 1947 up to 1951) then, they continued the 640 line, but since they did not allocate the sn range to a certain caliber, so they just used the SN they were at, mixing it with the 1640 production after 1952. The highest recorded SN for a 640 is in the 163000 range.
As for the stock variation, the big majority of the 640 came with beech stocks, except for the North American production (which is not called 640, just to add to the simplicity of the line - sarcasms) on which they started supplying walnut stocks in 1951. They started offering schnabel stocks - while continuing to offer the "beavertail fore arm style - for the 640 around SN 150 000, some very few were made with walnut stocks, but the stocks were also offered as aftermarket addition. Before 1951 the typical 640 they were only offered with beavertail stocks.
Hope that somewhat helps you...