Is this gas pipe installation OK?
No, it is not okay.  Make sure this is fixed before it's covered up.  I'd have to search through the code books to find all the relevant code sections, but simply looking at this there appears to be a few problems. 

I'm pretty sure you can't have connections like that in concealed location. So if this wall is going to be finished (covered with drywall), they have to be moved.

If the pipe is within a certain distance from the edge of the wood member it passes through, steel plates have to be used to protect the pipe.  

I'm not sure if non-rigid pipe is allowed in concealed locations, but I'm sure if it is, it has to be protected in some way.

Call your local government, and have this inspected.