I've been able to buy two 7C, but haven't come across a 7D in recent years.Given that I've been collecting for 20 years and have seen only 1-2 7c compared to a dozen 7d... the 'c' variety.
The D-cell is a straw-colored gold in person. It also seems to be part of the serial range from around 1992 when a large batch of gold D-cell Mags were made. The C-cell is late '90s and has a deeper color, more coppery but it doesn't look like the copper Mags I've seen photos of.
Still have a few including the brass version. I’ll dig them out and get a fresh picture or two if interested.They also did a small run of brass body gold plated minimags at one point. I traded my Marquis (pre-Solitaire) for one then later traded that for a gold plated 3aa Brinkmann Legend.
Speaking of Legends: