It appears more and more like fake news -- how could he have reported no assets year after year and not be charged with fraud -- doesn't make any sense
I found it fascinating that nobody has mentioned FERS as you did. After countless different searches all to no answer end i have
Social Security First, clearly social security is an asset — it’s no different than an inflation-adjusted annuity. However, for a variety of reasons it doesn’t belong on your balance sheet. To begin with you have many issues to consider which make it difficult to value the stream of payments you will receive from social security. https://bainbridgecf.org/assets/media/images/larry%20swedroe%20blog%201.pdf
I asked the question, 'Do congress members have to list their SS as an asset' in many different ways without success.
Maybe there is something more in the one above which explains why no one else has mentioned FERS re Johnson's failure to declare any assets.