Hope this helps

Found this whilst searching something else;
David Joyner's M1 Garand En Bloc collection

Good piece...

I have a 0 stamped early clip and the early blank clips with the notches cut-out have been around for awhile, some think they are Winchester. I think the 0 stamp is Springfield. My old friend Tom in NJ also has early clips with numbers too

It was stated that the early Winchester clips had the wrong location for the notches and had to be re-machined resulting in a clip with four notches ?Attachment 90800Attachment 90801

I believe that the problem WRA had with their early clips (much prior to their 'educational order' for rifles) was that SA changed the size and location (more than once) of the detent cut. Some could be revised and accepted by re-machining the size of the cut, but many were junked. WRA had a lot of trouble with ordnance changing dimensions of things and expecting WRA to go along. WRA felt they had a deal to make 'X' and if you changed it to 'Y', then the contract had to be changed and costs involved paid for. WRA asked to be dropped from making the M1 clip in 1943. I have an early clip, which I now believe to be a pre "WRA" one, stamped "1". It is the only one I have seen in over 20 years of looking.

Attachment 90804

During World War 2, clips were modified by installing a 3/16 or 1/4 in rod. This was perfect for cleaning your rifle as the rod kept the follower & slide out of the way when the cleaning rod was usedAttachment 90835Attachment 90836Attachment 90837