The one that I have does not have the standard 8mm x1.0 threads of standard adjusters. They do look very much like the one pictured earlier in the thread.
Performance engineering does modify 993 rockers. to use adjusters.
https://forums.pelicanparts.com/10620769-post13.html
From Neil later in the post.
Yes, these are 993 rocker arms. We use these for adjustable types as they are stronger and lighter than 911 types. 911 rocker arms are cast and 993 arms are forged.
The arms are purchased new, undergo a ratio check, pad check, crack checking, machining for the threaded bushing, additional modification if used for 911 cam housings, and finally after ultrasonic cleaning, sent out for DLC coating. Upon return, the shaft bores are honed for the clearance we specify and finally get assembled with the bushing. We use new rockers only if they are to be DLC coated as there is minimal contamination prior to DLC coating. Used rocker arms have too much embedded trash which makes the adhesion of the DCL too difficult to be certain of.
john