A couple years ago I purchased an M1 from a lgs, who acquired it through the CMP.  I seem to have lost the documentation stating it is from the CMP.

Is there anyway I could get a replacement certificate, or is it even worth having?

Thanks in advance.

From the CMP website under FAQ

Q?
WILL THE CMP RESEARCH A SERIAL NUMBER TO SEE IF IT HAD EVER BEEN SOLD BY THE DCM OR CMP?

A.
We will perform the research. Research often involves going through boxes of old records. Our files are only complete from 1996 to the present. We do have some earlier files, but know they are incomplete. We require a letter request with payment and we will respond by letter stating if we found anything, and if so – when we sold it and what model it was we actually sold. We will not identify original purchaser. Allow 2-3 weeks per serial number.

We regret not being able to perform this service for free. We receive dozens of requests each week and it can take up to one hour just to find that we do not have any record of a serial number being researched. Charge is $25.00 per serial number, prepaid, whether we find anything or not.

If interested, send letter to CMP, ATTN: Serial Number Research, 1401 Commerce Blvd., Anniston, AL 36207.

CMP will only give a  certificate to the original owner.
As stated above for $25 they will search to see if it was sold by them and if so they will issue a letter stating so . If its just a standard rebuilt Garand IMO its not worth the $25 to get the letter

Thanks. I feel its not worth it either, especially since it will never be sold  (by me).