It would seem the stabilizer in the top 63' dated diagram is experimental yet the bipod sling swivel appears to be production whereas in the diagram below the opposite looks to be true. Go figure. One other observation on the Ex. stabilizer above is the absence of the beefed up band on the back end of the muzzle portion like the one below.
Here are 3 examples of the forward E2 grip assy., the first from Do-Well mfg. the middle one made by Ray Kryza of SE Mich. sometime in the 70s and the one on the right is embossed with the name NE Inc. Ray's is obviously a reproduction.
The other shot is of an E2 stock liner and screws, the counter sunk flat head screw is correct with the liner w/ star washers and the other 2 screws I'm told were used without the liner on the early S.A. walnut E2 stocks.
Thanks Phinehas for the added info! Mr.Ray Kryza did good work but did not come close to the real article. I believe the same is true for the stabilizers in question, he did a quality reproduction but it is still easily recognized from the original.
I know that the third generation stabilizers that we possess are the real deal and legit.
Two of these are USGI E2 rubber butt pads but the one in the middle is a reproduction. Notice the difference in width on the top portion that fits between the hinges of the folding plate.
The underside shows the real difference between the fake and genuine article.
On the left the maker is ARGO DEV. CORP. and on the right the mfg. is N.E. Inc. I've also included a pic of the correct USGI screws.