I have been going through the exact same thing with mine. I have a metal DBM system that I picked up off of Ebay the other day but it doesnt have a trigger guard. I was like no worries I have several metal ones so I went ahead and bought it.. Well My metal trigger guards dont have the forward "TANG" (if thats the right way to put it) so I called savage. The lady tried to help me for almost a half hour in trying to find the right guard. I ended up ordering what I thought was the right ones. Well they were exactly like what I already had. I just happened to have a plastic one laying around from somewhere that fit perfectly. It seems that my DBM system has a little more cut out than the other models that I have where the trigger guard sits on top of the Mag well....

But as I stated the lady at Savage was super and tried her best to get me the right part. It was my final decision to order what I did. So my recommendation is to call Savage.

And ya Im still in search of a metal trigger guard with the "TANG" but in the searching is the fun!