I would never guarantee anything on these old guns.  

But, I would think it will work.  Even if it doesn’t, I would not weld up the fp hole.  I would elongate the small fp hole toward the bore center.  Then make a new firing pin that will fill the hole and hit the 22 rim.  This does take some lathe and mill work work.

I just finished doing this to a Remington #4 in 32 rimfire and it has worked fine so far.
Bob

It should work without any alteration. As mentioned, a 22 breechblock should not be too hard to find if you find you need one