Rust is ferric red water iron and an iron test tests for ferrous clear water iron which is dissolved into the water. Run water for a few minutes to get the pump to cycle 2-3 times and take a sample for testing or test for iron. Unless the water is discolored you don't have ferric iron in the sample. Your galvanized could be adding iron to the water but very little compared to the amount in the water recovering the well.
For the galvanized to be adding iron to the water, the water will have to sit in the pipe for hours. Unless you have acidic water and the outside of the pipe is all rusted.