You drill and tap holes in the back for a grease fitting, they hydraulically force them out, as well as beat on them prior to cutting the threads. The slide pins are not threaded.
At least you know WTF they are, to most guys this is like a space shuttle oring. Don't get me started, it's early and I haven't had a cocktail yet.......
In the past, I'd use heat to get them out but that was a crapshoot.
Use the small grease fitting, buy the tap and make sure you have the drill bit for it.
Such a pretty frame just waiting to break....
All our government does is distract us while they steal from us, misspend our tax $ and ruin our country