I'm going with "rivets" in this case. Not that I'm a full time riveter, anymore. Nor employed as a welder. But...
BTW, SMLE charger bridges are riveted assemblies. They look about the same when cut off nicely. Not so much when wrenched away!( would have more photos, but P'bucket is hardly working. Took about 20 minutes just to get to the tools album!)
Have a few 1888s and never thought the added charger guides were anything but riveted! But there may very well be welded examples out there as well.
---------- Post added at 11:27 AM ---------- Previous post was at 11:23 AM ----------
And what's with the crazy rectangular cutout on the left receiver wall just forward of the bolt stop?