..."Interchangable choke tubes were invented after the Model 12 was discontinued in 1964."...
from Fjestad blue book:
MODEL 12 SLIDE ACTION
- 12 (introduced 1914), 16 (introduced 1914), 20 (initial ga., mfg. 1912, 2 1/2 in. chamber mfg. until 1927), or 28 (introduced 1937) ga., 25 (20 ga. only, mfg. 1912-14), 26, 28, 30, or 32 in. standard, nickel, or stainless steel (scarce) barrel with or without rib (matted, solid, or VR), 2 9/16 (early 16 or 20 ga., until 1927, at ser. no. 464,565), 2 3/4 (became standard 1927) or 3 in. chamber, 6 shot, blue metal, various chokes, hammerless, plain pistol grip or straight walnut stock and forearm, marked Model 1912 from 1912-1919, approx. ser. no. 172,000. Mfg. 1912-1976.
Grading.... 100% ..98% ..95% ..90% ..80% ..70% ..60%
12 ga. ......$625 .$450 ..$350 .$325 .$250 .$200 ..$175
Subtract 50% if with factory Cutts compensator.
The following add-ons DO NOT apply to 28 ga. values.
Add 40%-50% for Win. solid rib.
Add 50%-60% for Win. milled VR.
Add 60% for each extra barrel(s).
Add 40%-50% for Win. special VR (offset barrel proofmark).
Source(s):
27th Edition Blue Book of Gun Values
these were external chokes, as opposed to modern in bbl chokes. they threaded onto slotted cutts comp tube. with them being such a detriment to collectors, i'd think them a good value for a shooter.
gunnie