Surface finish of Arduino Uno Rev3

Hello everyone!

I can't tell for sure what surface finish method they used for Uno. I was thinking either HASL/Immersion Tin/Immersion Silver.

Does anyone know?

https://store.arduino.cc/arduino-uno-rev3

Hard to tell without sectioning and placing under a microscope, all the pads are covered in solder paste
during production!

What's the issue?