Questions from a beginner looking to learn!

Hello everyone, I'm relatively new to the vintage omega world. I've done as much research on the internet regarding ref. Number, serial numbers etc... however there are a couple of questions I couldn't find the answer to and looking for someone more knowledgeable to help answer them.
I bought a vintage Constellation Quartz Ref.198.0114, bi color, and I wanted to ask if the observatory button on the back and the front part of the case are gold or just gold plated. I've attached photos of the watch. Grateful for any insight