It was definitely manufactured in 1946, since records from the company show 614 manufactured in 1946. The earliest in the SWCA database shows that K20X shipped in February, 1947. The latest 1947 shipment was K 83XX, so over 8000 Masterpiece revolvers were shipped that year in both K22 and K38. As stated, the only way to know for sure when the OP's Masterpiece was shipped is to get a letter.
Do you mean K83xx was the last K22 shipped in Nov 1947 even though higher K serial numbered K22's where shipped in Nov 1947?
No, but that is the highest entry in the SWCA database on the first pass. Over 8,000 could mean 10,000 or a little more, it is only an approximation of the numbers shipped that year.
I just checked both K22 and K38 Masterpiece revolvers again in the database and find the earliest 1948 shipped Masterpiece was K105XX, but also found additional numbers above that one that shipped very late 1947, so there is an overlap of 1947 and 1948 numbers for low K10,000 numbered revolvers.
I had K136 belongs to another member here now. JIM
The only reason I asked is your first post (above) confused me in that I own K22 s/n K872x and it shipped in Nov 47 (according to a letter from Roy). You said K83xx was the latest K22 shipped in Nov 47. So do I assume that K83xx shipped after K872x?
I show K8788 shipping in Feb 48 as well as K6888 shipping in Jan 48 so I know S&W didn't following s/n when shipping. K12566 shipped Dec 47 for example.