No problems are showing in the picture. Your boat looks great; way better than most. Miley used a one piece stem, sawn out of a big old piece of oak, so at both ends of the stem, the grain runs out at a rather extreme angle (the stem goes around a corner, but the grain runs in a straight line). That checking is pretty normal after all these years, and shouldn't be an issue. I think every Smith boat I have seen had at least a little of that going on. If the rest of the boat is in similar shape, you are ready to go. I might make a suggestion for the future, however. Someday, when you do decide to paint the boat, take that stem down to bare wood and soak CPES into it until it won't soak in any more. If you do a thorough job, the CPES will fill the checks and your paint film will remain uninterrupted instead of telegraphing the checks through the paint. I won't last forever, of course, but it will lengthen the time between needed paint jobs.
The very bottom left corner of your picture shows the most trouble-prone area on a Smith boat; the stem-to-keel joint. Yours looks tight as can be; not even a crack in the paint. Also, the hood ends, the ends of the planks where they are fastened to the stem, are in unusually good shape. Those are fir plywood planks, and they usually have a little more delamination showing at the ends than yours do. It's mostly a cosmetic thing, unless it gets really bad, just a slight flaking or chipping away of the outermost ply, but it sure is nice having them as solid as yours.
Good luck with your project. The canvas work should be fun. Right now my son and I are putting a new coaming on a 21' Fox boat; new breasthooks, steam-bent hoops, canvas, plus the dodger; the whole shebang.
