Looks like that batch sold out quick but there will be more
So .22 Conversion kits can fit all lowers. .380 can be turned into a 9 Mak or vice versa with an additional bolt and magazine. .32 acp is on its own due to the mag well but you can reuse the bolt.
I grabbed the non-threaded .22lr, and it runs perfect with cheap .22 ammo.