A series “0”, 23-jewels, hunter case, no less. Indeed a rare bird, that one! You did well to find a Howard dial that fits the hunter cased model. Movement is not marked Series “0”, which apparently is not uncommon. Here’s the skinny on it.
https://pocketwatchdatabase.com/search/result/e.-howard-watch-co.-keystone/1286140
I have 2 series 5s, a series 11, a series 4 (or 9), and an original E Howard series VII, 18-size. But no series “0”.
🤔 Indeed nice to have, especially being family. The listing (above) indicates these were made with stem setting, and lever setting. Yours appears to be stem set.