Street longevity of Motul Gear 300 gearbox oil
 

I just had my 1000km service on my new Suzuki Swift. Being the fussy bastard I am, I put some Mobil 1 0W-40 motor oil and Motul Gear 300 gearbox oil in, now wondering if it might have been an overkill. I probably won't be changing the oil until 15,000kms as per the service schedule, and was wondering if the gearbox oil will be alright for that distance?