Hi Courtney, this is not a SBR because it does not have a stock, it has a pistol brace. No tax stamp needed.
The difference between this and a SBR is the pistol brace, if you were to replace it with a stock, it would then be a SBR.
Stay safe & have a great day!

Hi Courtney and welcome. No, it has a Brace rather than a Shoulder Stock, so it is classified and sold as a standard handgun/pistol. A shoulder stock would make it a SBR requiring NFA registration and $200 Tax Stamp. Cheers, stay safe and enjoy!