Can a Flathead get oil in the radiator?

[hombres ruin]

Hi guys. We hear of water in the oil but can a Flathead get oil in the water. The reason I ask is this. I have a stock 41 coupe. New radiator and new top and bottom hoses. They have been on the ride for about year and a half . The rad is aluminum. It has distilled water and water wetter in it. I have a 7lb cap and at times I get what looks like dirt/mud under the cap it’s greasy to the touch.Its about a dime maybe less in size and watery not much at all. It’s on the most prominent end of the cap . The block is original and has 19800 miles on it. Looking in the rad I see what looks like scale ,pic enclosed. It’s been noticed by me for a while. I drained the radiator last week and no oil was present in the water. I flushed the rad out and filled it up. I did a combustion gas test with the kit and it was negative, I am not losing any water nor losing any oil . No water out the tail pipes nor smoke . It runs great and never has overheated .it has original heads and no water in the oil pain. Am I dealing with crud from the block or oil? Am I over reacting? Thanks for the advice/help