I have a TG-23 Metroplex and the Scamper I have looks like the one on the box not like the figure next to it. Now when I mention all black I am referring to the figure on the left and when I talk about grey and black it's the box art. Head and weapon are red for all and visor is blue for everyone far as i can tell.

 

TG-23 Scamper

 

I have the LG-EX Reissue of Metroplex and, though the box still depicts the Black/Grey Scamper, mine is totally black.
I don't know if this means that it was the case for the full run or if there may have been a running change, you'll need more LG-EX owners to chime in to figure that out.

 

Your the 3rd one that has said the all black and each said it's the LG-EX

 

I own most of the releases. I can confirm
US release Metro - Black and Gray (small symbol on hood)
SDCC - Black and Gray (small symbol)
TG-23 - Black and Gray (big symbol on hood)
LG-EX- All black (big symbol on hood)

 

The takara release tg23 so I say the lg ex may be a recolor
But lets ask @Nevermore more he is smart

 

But not all-knowing! I'm at work so I only have limited internet access, but the few photos I could look up confirm the all-black Scamper.

 

I did not even think about the symbol size.