Looks like a good ol fashioned Model 94C, made until 1984 or so. Until about 1968 or so American made firearms were not required to carry serial numbers so if yours does not have one, that ought to be the reason. They were real "everyman's weapon" in their heydays. We still have one like yours, and in 16 gauge too - still going strong after 50 plus years. Not likely to fetch anything significant on the used market, but if you have it proof tested and inspected by a competent gunsmith, it's alot of fun. A shame the 16 gauge is so underappreciated nowadays. It's a great all round gauge.
The model 94 C was also produced in 12 and 20 gauge.
Just a suggestion - if you can find Eley ammunition where you are, grab some and have fun. They still make almost the full range of shot sizes for the 16 gauge and are very well regarded worldwide.
