Signs of rust in Engine any Ideas

I live in Florida and have had many motors sit long periods of time, never had a problem like that. I would say it was some kind of leak in the motor maybe cracked block or head leaking into cylinder so didn't show in the the oil. Is the motor sleeved could have a problem there but I would be more suspect of the gaskets the can leak slightly when cold usually not an issue if its just a second or two and then seal with tempiture but if you couldn't get the engine started and it had seeped a little water in to cylinder then sat for 7 months well theres your problem wouldn't show since it's a small bit of moister moving thru the gasket. Those gaskets take a special technique to get to seal. Sorry but that's my best guess.