After doing one myself, it actually is reversable.

The only part that couldnt be reversed is a polishing they would do
on the surfaces. This is a minor step that they may or may not do.
This isnt something to worry about.

There are 2 components that are changed

The sear and the USB

Both can be replaced, returning it to a "stock" set up

The springs can also be changed out as well.

You really may want to try it yourself. Its not that hard.

Putting in Apex parts will probably take at most 25 mins.

Recontouring the stock parts to match the Apex is also not that hard
(The slide show (burwell) is very east to follow)

I chose the 2nd option and couldnt be happier