I have a Roma 2000 Giubileo LE which stinks in the way you described.
After much sniffing like a puppy I've concluded that the smell emanates from the ebonite feed.
No harm, it just stinks
And with regards to the "plating", it's the silvery/white metal portion that is plated; the yellow/orange portion is the unplated GOLD (gold is yellow, right?). The darker hue that you see on the unplated gold is due to tarnish, since the gold used to make the nib is not pure/24K gold (which does not oxidise), but 18K (75% gold) - it's the other metal(s) used in the gold alloy that oxidises. Regarding the "worn plating", it's due to imprecise application of the white metal plating going beyond its defined "limits" and encroaches into the unplated yellow parts.
Enjoy your Paragon in good health. It's a grail pen for many here including yours truly.
Edited by shahrincamille, 25 November 2015 - 05:14.