What is this on my MKII?

[Timmymc]

I recently refurbed a MKII  that I bought as a desk lamp on eBay years ago. The  lamp was very well-made  from completely  original, top to bottom MKII ( would break a collectors heart )  and stripped of every speck of paint. In fact for a long time I believed them to be plated. The body was in pristine condition! They used plug hole for wiring. My question is this. In the picture you'll see a small clump of ????. The rest of the body is perfect. The small shiny spot you see in it was from me examining it ( it's metal/steel and solid!) because I didn't notice it when painting. Anyone else seen this or have an idea what it is. Thanks y'all 

[Davejb]

I would think its casting slag from when being made, provided it did,nt interfere with overall shape, it would have passed inspection.

 

[pylon1357]

I have to agree, it looks like casting slag to me.