Safety repair help. (W/Pic's)

Traded for this rifle and has a broken model 70 safety shrould lock. How do I install the new shroud lock on my 1903A3 3-position safety? Backed out the pin and removed broken part. The new one won't depress down far enough to enable the pin to be re-installed. Is it as simple as fileing down the bottom so the pin will slide over the top of the new part?

http://i224.photobucket.com/albums/d...d/S6001777.jpg http://i224.photobucket.com/albums/d...d/S6001776.jpg
http://i224.photobucket.com/albums/d...d/S6001764.jpg