Background Check?

Hi all,

I'm joining a firm as a FT IB analyst in the summer and am yet to hear about the background check. Is it just a finger print or will there be some digging? There is a minor discrepancy in dates as my formal application reflects the dates I was paid by the firm, though my resume shows the dates that I "worked" for them. I obviously worked the dates I was paid but was also asked asked to keep researching their industry and to notify them of any interesting findings. While I did research the topic, I never communicated anything of interest to the firm. Not sure if the MDs I worked for will even remember asking me to keep looking into deals/ financings for another few weeks after the internship ended. Will the background check be conducted using my resume or formal application? Should I be worried? Nothing else on the resume will raise a red flag. GPA is accurate, work experiences are real, etc.

Thanks