Donny, most integral suppressors I've seen have a short barrel which the suppressor wraps around. The suppressor is usually quite long in comparison to this barrel whilst the barrel itself is usually quite short compared with an unsuppressed weapon of the same design. Whilst the suppressor can be removed for stripping, it's certainly part of the weapon proper. I believe that in most instances, the ported barrel (ie: one with holes or slots drilled into it to vent the gases) and the suppressor are seperate components.
There is usually a difference in design with purpose designed suppressed weapons vs regular firearms redesigned for an integral suppressor though.
In all of this, if the bullet isn't a subsonic load for a rifle type cartridge, the weapon won't be 'silent' (quite few are in real life) and regardless of the bullet report, the action of the weapon will still be 'noisy'.
The DeLisle silent carbine apparently has the lowest signature of any suppressed weapon, but the bolt to reload the rifle is quite noisy by all accounts. It should be noted here that it was a 45cal weapon with subsonic bullets, rather than a rifle calibre, supersonic bullet weapon.
Regards,
John