That's not how it works.
You either pay customs or you pay taxes, not both. If Oculus charges more to cover the taxes (as is usual in the EU), you shouldn't need to pay customs as well. If Oculus charges "taxes" and you need to pay customs as well, those taxes you payed are going straight into Oculus' pocket.
This.
Import duty is similar to VAT but not the same thing. They are usually cost-equivalent (else it causes a distorted market and tends to open up some oddball tax avoidance methods), though you often get hit with an extra handling charge in the case of customs.
If you're being charged VAT, then it's either because:
1) the product is being shipped from some location in Europe (99% of cases, since individually mailing parcels from America to the EU is very expensive compared to hauling a few cargo containers, then employing local couriers!)
2) a scam (rare)
3) You're buying digital goods (to avoid us Europeans buying our Steam games from an "foreign" company without paying any tax, since bits don't pass through customs). Rules for digital goods are new and likely to be quite complicated, but you'll see it if you compare Star Citizen/Elite Dangerous prices from their EU and American stores.
If you aren't being charged VAT then it's either because:
1) It's being shipped from outside Europe and a customs charge will apply instead.
2) VAT has already been paid (e.g. private non-international sales like ebay)
3) The shipper is evading tax (and will be in serious shit if they are caught).
Occulus will not claim to be including VAT if they aren't. This would be a VERY BAD THING for their accountants when they file their tax returns. They are a billion dollar company, not some mom&pop store that can be forgiven by the taxman for making elementary accounting mistakes.
Amazon/Ebay ship from the US and allow you to pre-pay the custom fees.
This is like how you can privately ship with Fed-Ex fro the US and tick a box marked "bill customs fees to seller".
This is not a scam. While Amazon are a bit dodgy, they aren't going to commit massive tax fraud or smuggling to make a few extra quid. Ebay sellers can probably fuck things up though, if they ship without following ebay's global seller instructions.
TL;DR:
Since the Dev kits were shipped from Europe, the consumer product will be too.
EU prices include all taxes. The price you pay Occulus is the only price you pay.