1969 Race Dart w/ 426 Hemi- garaged for 45+ years

I’m all onboard for not cranking it until going through it. There may be some really special parts in that you don’t want to get damaged besides just the block and heads. But, I’m wondering if it’s a factory race Hemi from another car or an over the counter piece. There should be a pad on the drivers side of the block in front of the manifold with some information stamped on it, as well as some I’d numbers possibly stamped elsewhere depending upon year. And casting date numbers, too.