From HKPro......reportedly from Vector to an end user....
"Removing the fake suppressor can be tricky. It is pressed on and then pinned. You can find the pin by looking around the back of the suppressor and finding the spot where we welded. It will be a bump. You then file or grind the bump off until you can see the outside profile of the 1/8" pin. The suppressor is aluminum and the pin is steel. When you see the pin, tap the opposite side of the suppressor and try to make the pin fall out. If is doesn't, you might have to drill down the side of the pin until you can get ahold of it or dig it out. It is anchored into one of the trilugs. That is the easy part. Because the suppressor is pressed on, usually it will not come off by just pulling on it. You will have to come out in front of the front sight tower about 1 3/4" and cut the suppressor off. This should miss the barrel. Then you will have to see where the trilugs are and aren't so you can split the suppressor piece down between two of the lugs. From what I have seen, people use a dremmel tools with a little cut off wheel on it. Be observant here because you down want to cut into the barrel. There is 1/8" space between the suppressor and the barrel so you can miss the barrel when cutting as long as you are between the lugs. If you cut all the way through the suppressor piece, you can insert a flat-blade screwdriver and pry it open a little and the piece should slide off"