Extended threaded barrels are a benefit, however not NECESSARY. Adco Firearms will turn down the end of your existing barrel and thread it. You can then thread on an adapter which will support the silencer/suppressor/muffler/can of your desire.
The issues I see it are that the extended barrel will be a better match as you have no bullet jump between the barrel and the silencer/suppresor/muffler/can. The threaded barrel with adapter issue will allow you to use the factory barrel, but has about 1/4" of a gap between the barrel and the silencer/suppressor/muffler/can.
Threading the existing barrel is invariably cheaper than buying an extended barrel and getting it threaded.
http://www.adcofirearms.com/