Hi
The 4A-107 is using the 3 group 4 elements taking lens 75mm F3.5 Tessar copy.
The viewing lens is a F2.8 lens. The view finder is the plastic fresnel screen which is bright.
In terms of performance, Red Gold should be the same as all the 4A-107. I have seen the blue copy (for Germany market), and also a Green version in Shanghai China. This is marketing and the cameras are solely for export.
The better made Seagull is the 4A-109 but the price is expensive. The top shuttle speed is 1/500 second. Adorama is selling for about US$280. Singapore price is about $450. China price is about RMB2500.
4A-107 uses a sliding level for shuttle speed and aperture selection. 4A-109 uses round knobs instead, which feels plasticky.
I have used both the 4A107/4A109 in about 10-20F winter and the cameras worked great. In terms of picture quality, they are the same. If the Red Gold is asking for more money than the 4A109, then I would go for the standard 4A107.
Note: You need to invest in an adaptor (34->46mm), a 81A high quality filter and a lens hood to really bring out the best quality of the 4A107.
Without the lens hood, the picture will be a disaster.
Another option to note is the 4B-1 (GC104 in US). The new 4B-1s are very well made and I bought 2 when in China. It is sold for about US$110. The lens is a 3 element lens and the taking lens is F3.5. The picture quality is superb for B&W people photo. Stopped down to F8 the quality is excellent.
4B-1 allows 645 or 6x6 format.
If you just want to have a taste of 6X6, maybe the 4B-1 is a good entry point. The only down side about 4B-1 is the shuttle might be damaged if you change shuttle speed after cocking it. Apart from that, it is a fine piece of equipment.
I remember an old magazine in UK featured the old Seagull 4B (with Chinese badge) and the pictures it produced was very similar to a Pentax 645 for magazine land scape shots.
Sorry I think this is a long winded answer.