Looks good but a few minor things ,
I believe that examples of the K22 "Heavy Masterpiece (which appeared in the 1950 circular ) did not ship until a few years later.

Also there was a brief overlap where both the 6" "Heavy Masterpiece" and tapered barrel Masterpiece were offered but ultimately the 6" tapered barrel version was discontinued but the tapered barrel style frame continued in the 4" (Combat) Masterpiece.

Also where it says:
"A 4” heavy-barreled Model 18 was produced for a while, beginning in 1986" is technically not correct.

The Model 18-4 was discontinued when S&W opted to produce the Model 17-5 and 17-6 in both 6" and 4" barrel lengths instead.

Also the 6 shot Model 18 and 17 were reintroduced in the new "Classic series" with IL and MIM parts and are instead based on a new style frame instead of the older "Heavy Masterpiece Model 17 frame.
In contrast both now have tapered barrels and Patridge Front sites.