Suppressors take as little as a week to obtain these days
... but there is the thorny issue of the background check and sign-off by the ranking law enforcement officer -- county sheriff or city chief of police -- in your home location. If he had a clean record, that would be possible, but the paper trail would certainly lead law enforcement to him eventually. How many people do you think buy those pistols?
The speculation about the $2000 WWII replica pistol is just that: speculation. What you saw on those videos was him clearing jams, not racking the manual action of an archaic firearm. The evidence is the complete cartridges found on the ground. That's what happens when you clear a jam: a live cartridge almost invariably gets ejected, whether it was the initial cause of the jam or just collateral ejecta from clearing the jam of a spent casing. The bottom line is that you don't eject live cartridges when you cycle a manual action.
What you saw was a garden variety semi-auto pistol with a silencer that was either homemade or sourced on the black market. The jams were probably caused by the silencer, which causes back-pressure that can affect the often-finicky functioning of a semi-auto pistol. The pistol can be tuned to compensate for that, but his clearly wasn't. Pro? No.