This was the warning Marlin issued. As you can see, it covers all models of the basic design. From a liability standpoint, SASS went along with Marlin's recommendation.
Marlin Issues Warning on Obsolete Shotguns
The age of these obsolete models is now 70 to 100 years. Unfortunately, Marlin has no records of manufacture such as materials, heat treatment procedures, or acceptance standards. This combination of age and unknown metallurgy and life history in a large percentage of these units has prompted the company to strongly recommend against these guns being fired.
Of major concern are failures in the firing system, but there is no clear cut failure mode or sequence of events leading to such failures.
1898, 16, 17, 19, 19S, 19G, 19N, 21, 24, 24G, 26, 30, 42, 49, 49N exposed hammer slide action shotguns.
28, 31, 43, 44, 53, 63 hammerless slide action shotguns.