At a Great Western Gun Show many years ago a collector from Norway had about 30 or 40 original sear safeties for sale (rivets were not included). They were cheap and some dealers were tripping over each other to purchase them.
Also, many years ago a number of Lugers appeared with sear safeties attached to the Lugers frame with brass rivets. (I doubt that the brass rivet is rugged enough to stand the stress of a lot of firing.) It was the opinion of experienced collectors at that time that these brass rivets were not original.
I have examined many sear safety Lugers and have never observed one with a brass rivet.
Looked at the sear safety Luger on Simpsons List and cannot tell for sure if the rivet is brass or steel. A call to Simpsons should determine that.
Note: the sear safety rivet and the cut at the top of the side plate should be in the white. Also note that the side plate cut is somewhat crude.
See also:
http://luger.gunboards.com/showthrea...ht=sear+safety
http://luger.gunboards.com/showthrea...ht=sear+safety
See fig. 1-13
Jan