Good news and bad news.. There is a website to look this up. drs.faa.gov/browse On the left navigate to design and production approvals, then TSO Approvals and LODAs. Under TSO select C23b, C23B, C23c, C23C, C23d, C23D, C23f.. (there's a really old C23 but that predates sport skydiving by a lot). You'll see all the TSO approvals. The information is *not* well organized. That's the bad news.
