The blog states that the SSA has 295 special agents who work in 66 offices across the United States.
“These investigators have full law enforcement authority, including executing search warrants and making arrests,” the blog post states. “Our investigators are similar to your State or local police officers.
SINCE WHEN???
Here's a 2007 list of all the Federal Agencies that have people taking firearms training:
2007 Federal Law Enforcment Basic Training Requirements
Note this is from 2007, BEFORE the Obama Administration, and most of these agencies have had armed agents for decades.
I honestly don't think there's an agency that is newly-armed in this administration.