From the 05/05/07 draft of the Third Edition of M14 Rifle History and Development by Lee Emerson copyright 2007:

"USGI M14 Stock Designs

The stock serves five basic functions for the M14 rifle: 1) reduces felt recoil to the operator 2) protects and holds the operating components 3) provides a comfortable gripping surface for the operator 4) allows attachment of a carry sling for hands free transport and 5) in some designs acts as a storage compartment for a cleaning kit.

The following list is a compilation of known USGI M14 stock variations and the month and year of the original drawings. Different part numbers were assigned to the stocks, stock subassemblies and stock assemblies. Typically, a stock subassembly consisted of the bare stock, the ferrule, the front sling swivel assembly and for wood stocks, the liner and two liner screws. The butt plate assembly and fasteners and rear sling swivel were added to the subassembly to form the stock assembly. The 1984 design M14 NM rifle stock lacks a stock liner and liner screws. The purpose of the ferrule was to protect the relatively thin front end of the stock.

1) September or October 1954 - T44E4: 7267084 - wood stock assembly (7267083 - bare stock)
2) September 1959 - M14: 7790702 - wood stock assembly (7790810 - stock subassembly)
3) December 1961 - M14 NM: 7791175 - wood stock assembly (7791280 - stock subassembly, 7791174 - bare stock)
4A) June 1964 - M14 NM: 11010281 wood stock assembly with routing and bedding (11010282 - stock subassembly, 7791174 - bare stock)
4B) June 1964 - M14: 11010264 - wood stock assembly (11010262 - stock subassembly, 11010263 - bare stock)
5) December 1965 - M14: 11686428 - reinforced fiberglass stock assembly (5910348 - stock subassembly with upper butt screw, nut and retainer, 11686427 - stock subassembly, 11686426 - bare stock)
6) May 1984 - M14 NM: 9392337 - wood stock assembly with routing and bedding (9381706 - stock subassembly, 9362638 - bare stock)"