At room temperature, probably, but at steam temperature, not likely. If it were me, I'd drill it out (and all others like it) and fit bronze bushes silver soldered in place.
Many designers of model engines specified tapped holes into the boiler shell for attaching things, Martin Evans in particular, even if only two full threads would be possible. Just not good practice. A boss through, or a tapped lug soldered on the outside of the shell under cleading is a much safer method.
JD