Valence's gun has a silencer when it falls
out of his case; then the silencer is gone for the rest of the scene.
When we first see the members of the Quorum, one shot pans across a few of them. The sign reading Leonis is next to the sign for Canceron. Later, we see a close-up of the representative from Canceron and the sign next to hers reads Picon.
When Starbuck and Apollo are questioning the man suspected of being an assassin who had hidden his gun in a false bottomed briefcase, Apollo slams the briefcase on the table and shouts "false bottom with anechoic coating to absorb X-Rays...". The term "Anechoic" means to absorb or deaden sound. It would have no effect on X-Rays.
In Act 1, when Starbuck sprays Apollo with the hose, she easily runs away when he gets the hose - despite limping a few moments before, due to her knee injury.