Congratulations on a fine purchase. In .38 Spl that would be an 1861 conversion if it had the navy grips.
Being .38 Spl, it will also take .38 Long Colt, which would be more historically accurate. I hear there are some available retail but maybe the best way to go with that is to reload your own. In your bore, you wouldn't need heeled bullets so reloading would be easy. Although a bit anemic, the .38LC can be fun to shoot. For CAS, it could have difficulty with knock-down targets, though. But what the heck, it's all about the fun, anyway.
Looking forward to hearing how it shoots.