I'm not trying to be stubborn here, its just that there are a few things which dont add up with the "Metal disc" theory...
For example-
1) Yes, on one posrtion of the edge it does look like there an edge of something sticking up, but on the other end the dge seems to fuse right into the lip of the tube..If there were a disc there, no matter how snuggly fit it would still show some sort of seam...But instead it seems to melt or fuse right into the lip..
2) The jagged edges on the edge which is sticking up...It doesnt look like the edge of a disc, but rather of somwthing which was probably chipped...
3) While Chris says theres a reflective metallic surface, I see nothing to indicate this...I do see light reflecting off of the D-ring attachment and lighing up a small dull area of the bottom, but it's not characteristic of the way light reflects off of metal..Its more characteristic of light reflecting off of a matte, or flat colored surface...
(And BTW, I have a chrome nut sitting on a piece of paper right now and the paper is indeed reflecting the light being cast from the nut...So paper can reflect light...Just not as sharply as metal.)
4) The base definitely looks like its some kind of chalky white texture which is, once again, not characteristic of metal..
Heres what Im thinking about the raised edge and fused edge-
Im thinkig the bottom was coated with Putty/epoxy (whatever you want to call it) and one side had more epxy than the other which left a raised area..
Then possibly this raised area was chipped off diring filming leaving a jagged edge which might look like the edge of a disc..