Carc/gearbox oil

I ordered some new carc/gearbox oil (motul gear 300 full synthetic), but the company sent me the wrong oil, same 75w90 but half-synthetic. So was going to sent them back, but they replied its absolutely fine to use a half synthetic.
Not convinced I still wanted to send the oil back, but I just checked Motul's oil selector site and for the GRiSO carc/gearbox they recommend MOTUL GEARBOX 80W-90 or the HD version, both of which are Mineral oils

Am I completely mixing up things? I thought the carc/gearbox oil had to be full synthetic?

Virtually any oil n the ballpark viscosity wise will be fine, mineral or synthetic. Yes, a synthetic is preferable simply because it is better at handling shear forces than a mineral but for a box like ours handling the power our bikes produce you could probably run just about anything.

The one caveat I'd give is to advise against using an 85/140 in either the gearbox or bevelbox because despite its cold flow rates being deemed to be adequate it is still slower than a 75/90 when cold and especially in the bevelbox I think this could cause an issue with the pinion nose bearing but I could also just be being paranoid.

We use a fully synth 75/90 in both gearbox and bevelbox. Never had a problem. Your supplier is a bit of a dill but it won't harm your bike using the oil he sent. Just use a different supplier next time if it worries you. It's less than a litre for both components. It's hardly going to break the bank.

Thanks Pete! I must have misremembered then, I could swear I read somewhere that its super important to use a full synthetic for the final drive but obviously I'm mistaken.

This is the oil they sent me:
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Quality is "technosynthese" I suspect their marketing department came up with that name