Randy, it is a pistol brace, the L shape is so you can put your arm over the bottom of the L to make it easier to hold with one hand. Since it's a pistol brace and not a stock there's no need for a tax stamp being handicapped does not change that, so absolutely no reason for a tax stamp right now. Like I said the atf is trying to change the definition of what a stock is to include pistol braces. So in the future it may be necessary to register with the atf but since you already own the firearm the atf is trying not to stir up to much of an uproar by giving out free one time tax stamps. Unfortunately the only way to find out if the atf changed the ruling is to Google it or id also recommend contacting your local FFL dealer/gunshop because they'll know the most up to date laws. Until the atf changes the ruling you won't be able to get a tax stamp for free and it's not necessary until they do but you would get one by filing out a form on the atf website. Hope this helps.

Randy, since the L shaped brace makes the classification as a Pistol, there is nothing else you need to do. There are different type braces that are easy to replace the L shaped one for better handling and still nothing would need to be done. I use this one and it feels better than the L shaped one and is more sturdy for hunting : budsgunshop.com/product_info.php/products_id/21103/sb+tactical+sbm401sb+sbm4+ar+brace+sbm4+ar+platforms+black+elasto-polymer --- Cheers and stay safe!