There is no safety lock on the release. The blade locks out just like a manual knife.
The brass button is is flush which helps to prevent accidental firing.
The blade has a small hole drilled to accommodate the locking pin when closed. It's not a knife I was seeking, but it walked up to the table and became part of a trade towards a Randall. The guy had this and two small Sebbies. It's in decent condition, but not mint by any means. The stamp is 2001.
Considering that it's a sheath knife, having the one hand option is pretty handy.
(Sorry about the iPhone pics)