Here is some information from
Bill Goforth. Mr. Goforth maintains a webpage here:
http://iverjohnsoncollector.x10hosting.com/AskMe.Htm
I'm not sure how dated the prices are.
SPORTSMAN DOUBLE ACTION MODEL 999 LARGE FRAME TOP BREAK . ----------1932-1952
Large frame double action top break revolver; Caliber 22 rimfire (short, long & long rifle) cylinder capacity 9 rounds, 22 Winchester Rim Fire (WRF)cylinder capacity 7 rounds; Safety rim cylinder; blue finish only; barrel length 6 inches (ribbed); Automatic cylinder stop; Sights: rear adjustable for windage only, Three different front sights used, full Blade, Partridge type & Partridge type pinned to barrel top rib, all non-adjustable; Finger rest trigger guard; One piece oversized checkered Walnut grips (birds head grip frame shape, Rice frame); frame mounted firing pin, hammer face is flat. Cylinder release is long pivoting lever on right side of frame (there are two different version of this). Serial numbered in its own series from 01 up to at least 89761 by the end of 1939. Starting in 1940 letter codes were used.
Early production until about 1933 the letter code “D” was used to denote double action
First Variation; round heavy weight ribbed barrel with Blade non-adjustable front sight ----1932- to before April 18,1933
Second Variation; adjustable front sight------------1933 (after 4-18-1933)-
Third Variation; firing pin moved to hammer-------------------------1934
Fourth Variation; three inch barrel was offered----------------------1935
Fifth Variation; two patent dates marked on cylinder (before there was only one)---1936 (after 3-17)-1937
Sixth Variation; top of barrel markings moved to right side of barrel---------------1937-1939
Seventh Variation; 22 WFR caliber dropped, 3 inch barrel dropped--------------1940-1941
Eight Variation; one piece over size plastic grips are standard, limited production during WWII years----1942-1952
VALUE: 100%=$425 60%=$195 Add 15% premium for 1st Variation; %0% for 22WRF caliber; 30% for 3” barrel (scarce)
MODEL 999 SPORTSMAN SECOND MODEL (NEW FRAME)-------1953-1972
Top Break, Double Action, 22 Long Rifle Caliber, 9 shot, Blue Finish, Barrel Length 6 inches, Adjustable Sights
VALUE: NIB:=$425, 95%=$365, 60%=$195
MODEL 999 SILVER SPORTSMAN--------------------------1963-1966
Top Break, Double Action, 22 Long Rifle Caliber, 9 shot, Chrome Finish, Barrel Length 6 inches only, serial number letter codes Z, AA, AB only
VALUE: (very seldom seen) 100%=$450 60%=$325
MODEL 999 SPORTSMAN THIRD MODEL (TRANSFER BAR IGNITION)-----------1973-1986
Top Break, Double Action, 22 Long Rifle Caliber, 9 shot, Blue Finish, Barrel Length 4 & 6 inches (4 inch not added until 1979, Adjustable Sights. In 1979 Only the Model name was advertised as Model 999 Automatic-Ejecting and it was offered in that year only in 32 S&W Long caliber, 6 shot.
VALUE: NIB:=$425, 95%=$350, 60%=$175
MODEL 999 SPORTSMAN I OF 999 (TRANSFER BAR IGNITION)------1979-1986
Engraved with Fitted Wood Case, Top Break, Double Action, 22 Long Rifle Caliber, 9 shot, Blue Finish, Barrel Length 6 inches, Adjustable Sights VALUE: Collector value only if unfired, with all original tags, manuals, commemorative medallion, wooden presentation case and cardboard box;
100%=$700+ if in other than described condition it is valued as the Model 999 3rd Model plus 20% premium for engraving.
Again, I take no credit for compiling this information. The above is the work of
Bill Goforth.