Having worked as a welder for the last 28 years, I'd bet my house that the lug is either MIG or TIG welded. You can see plainly where the lug edge is cut to allow for penetration, you can see clearly where the weld is ground, and at teh edges you can clearly see the edges of the weld puddle. While it is possible that the welding process is performed by a robot, I'd bet my bottom dollar there is some fella up there wishing he got paid more for making all the great welds he makes......
Electron welding is super a hitech process that is well beyond the means of a company makeing a product like the NEF.
If in doubt, TC and SSK and Bullberry use TIG welding to make their barrels, why should we think that NEF uses a technology that is a speciality even in the aerospace industry?
But don't take my word for it, call and ask.