JOB Application as Veteran

Hello everyone so I recently applied for a USPS job that is like 24 minutes away from where I live. I recently separated as of September as a E5. During the application process I have put veterans preference and was able to get 10 points for that due to 30% disability. I also saw that there was a back ground investigation. Would me having a Top Secret/SCI clearance help with that or would they make another back ground investigation? Also what is the possibility for a veteran to get the job like me? Also the job is PSE SALES & SVCS/DISTRIBUTION ASSOCIATE. Thank yall for your time.