The two were accused of attacking the group during a PDRC demonstration against then-prime minister Yingluck Shinawatra while passing the building.
They were charged with possessing weapons, carrying weapons in public areas, and attempted murder.
No-one was injured or killed in the incident.
The first court to hear the case ruled that former red-shirt guard Narongsak Plai-aram and Thanin Sinthusonthichart be sentenced to 43 years and four months each.
The Appeal Court later reduced the jail term for Narongsak to 35 years and four months, while overturning the verdict against Thanin due to insufficient evidence.
The Supreme Court in December upheld the Appeals Court’s ruling.
It was today read to the plaintiffs’ prosecutors again.