Check out Yashica-guy.com for more info on these. I used to have a set, but didn't like them too much. As I recall, the wide makes a GSN about 35mm and the tele makes it about 70mm. Not a huge difference.
Also, you need to do some "focus adjusting". You focus through the rangefinder then transfer the distance to the auxiliary lens. Or something like that.
To me it was more trouble than it was worth.
I see that you have them mounted on an SLR, I always thought they would only work on a GSN. Did they work on that lens?