Absolutely, that boiler has many other pinholes ready
to pop thru, If you tried to grind the rusty area to clean
metal you would have, well, not much left.
Mine was a Vertical linemar boiler and I have a fix but
it is not apropos for a horizontal boiler nor mixed company.
Only for a madman like me.
When setting up a new boiler try and keep your imagination
in check. You probably need only a few pounds of pressure
to make it go so you won't need a boiler good to 60psi. Don't
knock yourself out. There may be something out there, ready
to go, for use as a low-pressure boiler.
Good Luck,
Wayne