How to know which Gapps version is installed? How to know which Gapps version is installed in official Roms. I've a Archos 45b Helium with Android 4.4.4 installed.
In SDK package of Android, there's a little tools called "aapt" which gives you information about the version:

#~:./aapt dump badging GoogleServicesFramework.apk 
package: name='com.google.android.gsf' versionCode='19' versionName='4.4.4-1288895'
sdkVersion:'19'
targetSdkVersion:'19'

#~:/aapt dump badging GoogleLoginService.apk 
package: name='com.google.android.gsf.login' versionCode='19' versionName='4.4.4-1227136'
sdkVersion:'8'
targetSdkVersion:'17'

#~:/aapt dump badging GmsCore.apk 
package: name='com.google.android.gms' versionCode='5089038' versionName='5.0.89 (1307510-038)'
sdkVersion:'9'
targetSdkVersion:'19'


I did these commands in a terminal on my linux workstation, after exported the APK files from my /system/priv-app folder was in my phone.