Mr. Goforth was prolific on several forums and never hesitated to provide information from his research/books. This is from another forum post by Mr. Goforth.
Iver Johnson .22 Supershot Sealed Eight | The Firearms Forum :
22 SUPERSHOT SEALED EIGHT FIRST MODEL
(LARGE FRAME----------------------------------1932-1941
Features HAMMER THE HAMMER ACTION. This revolver also features a cylinder with recessed chambers that fully enclose the cartridge case head. Large frame top break marked on left side of barrel “22 SUPERSHOT SEALED EIGHT”. Finish: blue only; Barrel length 6 inches: Oversize checkered wood grips; Caliber .22 rimfire with 8 rounds cylinder capacity; Weight 24 ounces. Height with out grips 3 7/8 inches; Frame length 5 inches; Overall length 10 ¾ inches. The 1938 catalog gives this model as well as others Model numbers: Model 88 fixed sights, Model 833 adjustable rear sight, Model 834 adjustable rear sight and adjustable finger rest. . Main serial number location on left side of grip frame grips must be removed to see. First Models will have serial numbers below L26601
VALUE: 100%=$275 60%=$150
22 SUPERSHOT SEALED EIGHT SECOND MODEL
(LARGE FRAME)--------------------------------1947-1954
Featured the HAMMER THE HAMMER ACTION and the recessed cylinder of the first model. The 22 SUPERSHOT SEALED EIGHT was brought back after WW II almost intact. The grip frame was altered to give it more weight. The model numbers were not changed. The barrel shape was changed and a new 4 ½ length added late in its production life. The new barrel shape added even more weight. Caliber: 22 rimfire with 8 rounds cylinder capacity; Weight: 28 ounces; Frame height with out grips 3 7/8 inches; Frame length 5 inches; overall length 10 ¾ inches. The specifications that changed after the new barrel length and shape are; Weight 6 inch barrel 28 ¾ ounces 4½ inch barrel 26 ¾ ounces; Overall length 4½ inch barrel 9 ¼ inches. The new barrel shape is the same as used on the later Third Model. Main serial number location on left side of grip frame grips must be removed to see. Second Models will have serial numbers above L26600
VALUE: 100%=$275 60%=$150
22 SUPERSHOT THIRD MODEL
(AKA MODEL 844)-------------------------1955-1957
Features the HAMMER THE HAMMER ACTION. Known as the Model 844 the third model 22 Supershot is the last of a line of top break revolvers that can trace it ancestry to 1894 when the Safety Automatic revolver First Model was introduced. The only difference that can be seen between the third model and late production second models is the cylinder, which is unfluted on the third model. Only offered with a blue finish and large oversized checkered wood grips. The barrel is flat sided round, round on the bottom with a full length rib. Caliber 22 rimfire with 8 rounds cylinder capacity; Cylinder has recessed chambers and flash control front rim; Barrel length: 4 ½ inches and 6 inches; Sights are fully adjustable; Weight: with 4 ½ inch barrel 24 ounces with 6 inch barrel 27 ounces; Frame height 3 7/8 inches; Frame length 5 inches; overall length: with 4 ½ inch barrel 9 ¼ inches, with 6 inch barrel 10 ¾ inches. Main serial number location on left side of grip frame grips must be removed to see. This model will be marked MODEL 844.
VALUE: 100%=$300 60%=$175