No, but I would use some anti-seize on the bolt threads.
Don't see any signs of crack travel into the water jacket but it would be hard to spot with the unsmooth surface there. found a helicoil in the head bolt hole after we noticed a water leak from a blown paper gasket. Sorry should have said crack at head bolt hole on block. had a senior moment. :-)
Looks like the one opposite is cracked too.
You might put a helicoil there as well. At least the hole for the bolt should stop the crack from spreading. Be sure to check your block well for other cracks such as between valve seat and cylinder. This type crack is often caused by overheating. Especially it happens when someone pours cold water into an overheated engine without letting it cool off first.
Norm
I am curious what year block that is? Earlier blocks seem to be more prone to cracking that way. If I recall correctly, my '13 has five helicoils in it. Early blocks are rare enough and desirable enough that you can't just move on to another block for a few bad threads.
I do think that I would Helicoil that other hole also. Beyond that, No, I wouldn't worry too much about those.
Drive carefully, and enjoy, W2
This is a 1926 engine. that has std pistons in her and just had a refresh a couple years ago before my friend got it. new rings and valve job and new babbit on crank and rods
I have heard that the '26/'27 blocks are more prone to cracking also. Looks like that may be so. Still, I would run it and enjoy it as long as it is a good, reasonably sound, engine. Many cars have been run for lots of years and many miles with that sort of "captive" crack. The cracks that are of greatest concern are the ones running from valve seats down into chambers or cylinders. Those are the ones that can get stressed while running and continue to grow quickly.
The other ones to be concerned about are in the main bearing support webs. Each fire in each rotation of the engine hammers those longer and wider, eventually breaking out the bearing support.
When the engine requires a major rebuild. When the cylinders have to be bored and the main bearings properly poured and bored. That is the time when you consider properly repairing all the little issues. In order to weld the small cracks, the block has to be heated enough in that process to lose the mains and maybe warp the cylinders anyway.
In the meantime, lesser water jacket cracks and relatively minor captive cracks can be run and usually (not always) not cause much trouble.
That is my opinion and experience.
Drive carefully, and enjoy, W2
The crack you mention is a common one on Model T engines, doesn't matter what year and even Model A's "It's a stress crack."
If left cracked the chance of the head bolt leaking water is probable.
Two pictures I have shown: typical model T cracks and afterwards the repairs through metal stitching.