That's classic Sinclair architecture. The similar styled additional building makes your site unique. Good luck with your project. We'd love to see photos of the progress. Post questions or "wanted" ads and you'll find we may be able to help.
Yes, it is unique. So far we've been told that the secondary building was used over the years as several different diners, and most recently a beauty parlor. The station owner stopped selling gas in the late 80's-early 90's but kept it on as auto repair and, eventually, state inspection station only.
Since I started my career with ARCO (Atlantic Richfield), it's kind of "fate" we ended up getting this station. I'll post updates as we progress.
I'm not sure how we'll address the signage. I've been scouring eBay and the net and the full-size signage is hard to find or beat up pretty bad. Once we get closer, I'll have to decide if we go with "what we can find" or re-create the signage.