Legality of "fake" pistol muzzle brakes/suppressors
I recently looked at purchasing a Ruger P90 .45ACP pistol and wanted to do some research before making the plunge. This looks like a nice gun but comes with three extra accessories and I don't know if they are legal after doing some research. These are a threaded barrel, some type of compensator that looks similar to an oversized flash hider for an AR-15 or similar. It is a long cylinder with slots cut into it. This gun also comes with a fake suppressor that must just be for looks. I really don't see a whole lot of point to either of these attachments and don't consider them of value. The gun alone is a pretty good deal even if I leave the attachments with the prior owner.
Here are some details on the parts. There are no markings of any type on the threaded barrel or the the two attachments. The stock barrel says ".45 ACP" but there is nothing on the aftermarket one. There is a paper I was able to look at inside the package that says "Federal Arms Corp. of America" and has a phone number of 612-780-8780. The fake suppressor is listed with a model of "H1911FS" but this doesn't show up anywhere online. I tried calling the number and it didn't exist.
After doing some research, it looks like some attachments like this are considered to be suppressors and are not legal without the proper stamps. I am suspect of these parts and were wondering if there is a reason you can't find anything about them online now. I may just try to get the gun with the stock barrel and nothing else.
Does MO have some odd state law that we don't know about? Even in NY a threaded barrel on a pistol is OK.
The suppressor is only a suppressor if is suppresses sound. They should be tested so that they do not, but beyond how it is advertised, the only way to know for sure it to test it yourself and at that point it would be too late. Fake cans are fairly common, if you aren't comfortable with it, don't buy the fake can. Is there any particular reason that you are worried?