Noticed rust on engine pulleys on this car I'm thinking about buying. Should I be concerned?

No, that is normal if the vehicle has not been run for a little while. Thanks Master Auto Technicians

We have found slight rust like you have described but even more rust underneath a vehicle that is from a Northern climate. My suggestion is to have any vehicle you are thinking about buying looked at by a professional. This simple action can sometimes save you thousands of dollars. I hope this helps.