Probably not. Although the No.4 grew from the No.1, there are only a few common parts.
I would caution you not to meddle with SAFETY devices for operator COMFORT. Even if it fits, there is no guarantee that it will always and positively engage each of the required surfaces with sufficient resistence to work properly.
In my modest experience, the parts were designed by men with fighting experience to be easy to reach and function. If you are still unhappy, get a spare. A gunsmith can weld / screw / bolt on whatever lengthener you need.




























