Did you call them and give them a chance to make it right? If not, prepare to get flamed. The original ones in your CETME were Spainish CETME rollers, which if I remember correctly look slight different than later G3 rollers. Most of the G3 parts were redesigned at least once during the issue life of the rifle; it's what German's do. It is also possible that MP5, G33, HK21, HK23E rollers are different and that is what was sent to you. I don't have any of those bolts to look at, but the CETME rollers and G3 rollers that I am looking at are slightly different.