The unlocking lever should be to the right of center when locked up, it will gravitate gradually to the left as the locking lug wears.
This can be repaired by a good gunsmith, but the cost may outstrip the value of the gun.
economy grade double gun is of the first type with coil strikers or the later type with conventional hammers comes in 1930s guns where for a few years both types were apparently made at the same time. From 1936 on the 311 made on what is usually called a 311 action, utilizing conventional hammers.
If you find a fairly solid gun, the Stevens usually go for anywhere from 0-0, Fox B's are usually 0-0 more for a given gauge; 16 gauge guns were discontinued in the early 1970's and will bring a premium (The other gauges were built until the late '80s).
Having access to Savage's catalogs is the only real way to see what was offered in any one 'model' year.
I'd love to find a collection of catalogs reasonably priced, a bit of the history of what people wanted back then.
This includes both the Stevens 311 and its model variations, as well as the Fox B.
It's hard to figure what was on Savage's mind, from the differences in models from year to year.
Parts may be difficult to find, depending on what it is, but all gauges will interchange firing pins and retainer screws, hammers, mainsprings, safeties and sears.