Honestly, you would be hard up to tell the difference between gold and brass plating when they are both polished like that. It is not much more than acting as a selling point to say yes it is genuine gold plated, but that seems to be what the market wants (something to differentiate over and above the standard).

The only major difference is that pure 24k has a slightly more yellow colour to it. Once you introduce "impurities" to strengthen the gold and bring it down to say 22k or 18k it looks exactly the same as brass so I would just go with brass.

RE: The legs
A soft cloth with Brasso every once in a while takes care of any dullness, but generally they hold up well.

Brass would have to be clear coated otherwise it very quickly starts to tarnish and darken.
When you clear coat brass it does go a slightly darker colour.

I have had several plaques gold plated but at one stage I was just polishing the brass and clearcoating it, the gold looks 100% brighter and overall better product because no clearcoat is required.

Two drawbacks to gold:
1. The price has gone up over the last couple of years.
2. It is soft and will wear off with time