The Lefever was mfg. in 1935.
If it is a double, remove barrel and you will see it along with serial #.
The date of manufacture for a Lefever Arms Company double barrel shotgun can typically be determined by its serial number, but specific records for Lefever shotguns are limited. For serial number 351624, it is generally estimated to have been manufactured around the early 1920s. For a precise date, you may need to consult a dedicated firearms historian or reference guide specific to Lefever shotguns.
around $6000
estimated value of a double-barrel J T randall shotgun
1927
Requires professional appraisal.
Turn of the century.
The Lefever Model H double barrel shotgun with a serial number of 30025 was manufactured in 1908. Lefever Arms Company produced this model between 1900 and 1915, and the serial numbers can help pinpoint the production year.
The best that I can do is say that the Lefever Nitro special was made from 1921-1948.
Blue Book of Gun Values
To get a parts breakdown you would need to take the shotgun into a gun store. The store will be able to provide an estimate, or order new parts.