Photo 1 is it.
I just looked at my guide again. There is a rivet in the middle of the curve at the upper end. Whatever is attached to this rivet--maybe it was a threaded bolt--is what I cut off (and isn't on the newest guide). It puts all the holding of the end of the guide solely on the adjustment screw, but as S-Squid has noted you can shim the end to keep it in place if the screw tends to loosen. I have not had any issues in 6 months since I used this fix on my guide.
I found my original post on this fix: I made one more adjustment to my shooting guide today that made a big difference, so I thought I'd pass it along. I have made all the normal adjustments and installed the more powerful coil, which has helped. After time my percentage of accurate auto launches was decreasing so I thought I'd take another look at it. Stern had sent me the new and "improved" metal shooting lane guide. I tried to install it and found the adjustment mounting tab was in the wrong place--and I didn't want to drill another hole in the playfield. Both guides are very similar, except the new one does not have the threaded rod riveted onto the guide near the adjustment screw tab. So, I cut the one off of my original guide, filed down a small burr that was right at the end of the guide, polished the guide and put it back on. Oh, ho--a little more adjustment is available with that rod gone! I had to raise the tip of the upper right flipper to make use of that adjustment, but now auto launch is at 100%--and it has never been that good. The only neg to raising the flipper a smidge is that the ball will not loop all the way around to the lower right flipper, but I can live with that. Another plus is the loop shot is way easier to hit with this new alignment--so I like that a lot.