It takes a lot of code edits. I kind of already answered this here:
http://forum.xda-developers.com/showpost.php?p=33782818&postcount=80.
But, the AOSP one is built-in already, it's just that Moto has overlayed their lockscreen on top of it - you would need to edit the zz_moto_keyguard_unlock_widget.xml in framework-res.apk/res/layout.. Erase everything in that stock xml and replace with this to get the AOSP one to show up:
Code:
<?xml version="1.0" encoding="utf-8"?>
<com.android.internal.widget.multiwaveview.MultiWaveView android:orientation="horizontal" android:id="@id/unlock_widget" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_alignParentBottom="true" android:targetDescriptions="@array/lockscreen_target_descriptions_with_camera" android:directionDescriptions="@array/lockscreen_direction_descriptions" android:targetDrawables="@array/lockscreen_targets_with_camera" android:handleDrawable="@drawable/ic_lockscreen_handle" android:rightChevronDrawable="@drawable/ic_lockscreen_chevron_right" android:waveDrawable="@drawable/ic_lockscreen_outerring" android:outerRadius="@dimen/multiwaveview_target_placement_radius" android:hitRadius="@dimen/multiwaveview_hit_radius" android:vibrationDuration="20" android:snapMargin="@dimen/multiwaveview_snap_margin" android:feedbackCount="3" android:verticalOffset="0.0dip" android:horizontalOffset="0.0dip"
xmlns:android="http://schemas.android.com/apk/res/android" />
Then, to add a couple more widgets on the aosp lock widget, you would need to edit the smali code android.policy.jar, add some images to the drawable-hdpi folder and update the arrays.xml and strings.xml in /res/values, recompile the framework-res.apk, then decompile the newly modded one to get your new resource ids from the public.xml and put those in the android.policy java code.. and to change the layout of the locksreen completely, you would need to edit the keyguard_screen_tab_unlock.xml in framework-res.apk/res/layout.
So, in short, no - there is no easy way.