The exact value of a Stevens 12 gauge model g20a is actually dependent on a couple things. Some of these things would be the age and condition.
No way of knowing without a serial number /model number to identify what type of .410 gauge stevens you have.
model 77 does not have a serial number,they were made before serial numbers were required
If it was manufactured before 1968 it probably doesn't have one.
Your stevens model 9478 was made by savage/stevens between the years 1978-1985.
The Stevens Savage Model 124 12 gauge shotgun was made from 1949 to 1954. The serial number will signify the actual year of manufacture.
The serial number range for the Stevens model 520-30 military shotguns is from 30,000-70,000.As to the year of manufacture you will probably have to contact Savage/Stevens directly.
Stevens, sold at Montgomery Wards.
Check the barrel and receiver. Sn's were not required before 1968
Your stevens model 9478 shotgun was made during the years 1978-1985.while serial numbers were on the shotguns I do not believe that serial number records were kept as to the year of production.
i have a model 200 20 gauge and i belive it was made in 1918