I think that sign is fairly new. I don't recall seeing it before and I've made a few trips there this year.
Last post in that thread by eldirector:
"Digging around... Looks like the Senate amended the firearms part out.
Bastiges.
Appears in the Placed on Calendar Senate, but not then in the Engrossed Amendment Senate."
Sounds like once again, .gov may have pulled a fast one on us.