I am not aware that an employer will ask for your salary throughout your entire career, most likely background checks are done against your last employer.
You will be asked your current salary not what you earned a couple of years ago. I think you are too concerned about background checks even though you have not passed the assessment center yet.
My advice is to take it one step at a time, focus on your assessment center and never lie about anything this includes joining and leaving dates, this way you do not have to worry no matter what type of verification they do.
Hey, Thanks you right!! i'm worried too much about verification checks ..it is all because i have some hickups in my careers. And also as you mentioned i should get through with my Assessment Centre first :-) and start to think qualify that at first instance...
If you have gone through assessment process recently, appreciate if you can share the topic or some hits of Group Exercise plz.