A short look at Glock's website shows no threaded barrels standard from the factory. No barrels offered in the Glock website store are threaded. The USPSA rules state aftermarket barrels are allowed provided they are the same length, contour and caliber as original factory standard. I don't think threaded is the same contour as the standard barrel. Not legal for Production, but play in Limited, L10 and Open all you like.