eq 318 magnum heads
Yup, that and leftover machining debris in the ports-
@318willrun did a nice video on what he found with the "ready to run" heads.
Expect to tear them down and check 'em over before using them.
Since the cost of the RTR heads, and the SpeedMaster bare heads + hardware is so close I'd be tempted to go with the bare heads since you'd be tearing them down anyhow... plus you get to use the pieces you want (as opposed to the "pieces you get") when you (re)assemble them.