Looks beautiful Congratulations!
According to the Atlas / Monniot Guerlain bible, this beauty should be standing a whopping 20.8cm tall! Whilst this book is a treasure-trove of information and its lists quite extensive, strangely there is no specific information as to when the 125ml flacon was created, though it does list it as 'currently available' at the time this book went to print (1997). The likelihood is therefore that your bottle is late 80s - late 90s in vintage.
Enjoy it and treasure it!