Surprisingly I don't know much about these bolts other then they are very rare according to PTP and from what I've see over the years. I've only seen like 1 picture of these before and knew nothing about them. My experience so far with this bolt is that its AWESOME! Actually feels like it cycle faster and with a little less kick. Is yours gold with slits in the back for air venting?
If anyone has info on this bolt I'd love to know more.
The main advantage is the weight. Changing out the steel AGD regulator back for the Air America aluminum one will save about 4oz off the whole valve. I've been using these now for a few months and played a full day with one on my pump mag a few weekends ago. They act the same as the normal AGD reg, but they do not have the locking pin so that they don't unscrew themselves. In my experience I haven't seen a valve unscrew itself, but it's still a thing to note regarding the safety of these backs. The SFL Emag doesn't have a channel for the safety pin so I'm assuming they didn't see an issue with the valve unscrewing either. The classic valve tends to be a little looser then an emag valve but I still feel, with normal use, these aluminum valve backs will work just fine.
Here is a weight comparison: