The images you reference are for silencer adapters and can be purchased at CMR Classic Firearms
www.cmrfirearms.com. Last time I looked, they were125usd. And, they are like ww2 era. Only problem, these adapters are for .30 luger caliber barrels only. Now, I have the real deal for my 9mm lugers that I bought from DAQ Couplers. What you see here is a DAQ coupler that has a 5/8-11 thread. That’s the only thread available. Then, there is a 5/8-11 to ½-28 adapter. Then there is the YHM Cobra suppressor. I have purchase these couplers from DAQ earlier and had Kenneth Stuteville at Sniper’s Hide re-cut the thread to ½-28. But, Kenneth has drop-off the Hide’s forums and doesn’t answer his emails. I still plan to have these threads re-cut so I don’t need the middle adapter. (DAQ - Closeout of P-38 & Luger couplings with 5/8-11 threads. $25. each.
www.muzzlecouplings.com)
The photo's shown above were found on the net. I've seen them around for years.
And, surprisingly, the sights just clear the top of the suppressor.