Early bolt catch

Early bolt catch in a Colt SP1 (did not come that way). Just how early is this type of bolt catch ? pre 1963 ?

On the left photo is the early and later on the right photoAttachment 16063Attachment 16064

Late 1964.

Earliest: Colt mod. 601 and early 602s 1959-1963

https://www.milsurps.com/images/impo...oltcatch-1.jpg https://www.milsurps.com/images/impo...ltcatch2-1.jpg

Mid or transitional bolt catch: late mod. 602, very early XM16E1s, very early mod. 604s, and very early Colt SP1s 1964-1965

https://www.milsurps.com/images/impo...oltcatch-1.jpg https://www.milsurps.com/images/impo...oltcatch-1.jpg

Late bolt catch type: 1964 to current.
But there are early, mid, and late types of the last type. I do not know the years this occurred.

https://www.milsurps.com/images/impo...latelate-1.jpg

Thanks for the photo, the bolt catch on the left in my photo is the early 1959-63 (which is what I thought). The second photos are bolt catches that I have seen in early three and four digit Colt SP-1 rifles, could have lasted even longer ? On your third bolt catch in your third photo, I have seen that variation (with the slight bevel) in Colt SP-1 rifles in the early 50,000 serial number range.

Thanks for posting the photos RCS