Exactly.
It's not at all unusual to see older ratchets, even high-end pieces like SnapOn, that have no release button on top.
You just pull the socket off...or as Tim says, pry it off with a flat-blade screwdriver if it's particularly tight.
And I have a few larger drives where one has to be careful to only use sockets with holes drilled in the retainer pin location, as the square-shouldered detent pin can not be depressed any other way than by using a small round rod.