Purchased a cougar at auction recently and ordered a brownell guide rod assy (captive rod) for it. I have not fired yet but noticed a difference in the tip that goes into the frame. The replacement has a steel double cup on the end that sticks into the hole into the frame where as the existing has but one. Has their been changes on the cougar since mfged? The length is the same, I don't think it makes a great deal of difference but would like to know before range time.