[RC one]

In July, 1976 Paddock landed a letter carrier position where he spent two years before moving on to the Internal Revenue Service as an Internal Revenue Agent. While it remains unclear in which division of the IRS Paddock worked, a spokesperson with OPM says he spent 6 years with the IRS before he ended up in the auditing department of the Defense Contract Audit Agency.

[SauronOfMordor]

In 1976 he would have been around 23. My guess is he worked for the post office while working on his accounting degree, then applied to the IRS.