No, facelifting is not illegal. I have seen thousands of SUVs, like Prado and Land Cruiser(s) being 2010 models by the manufacturing date, and having the latest facelift of 2019 and onward.
There are no disadvantages either, as long as the vehicle is in optimal condition, the purchaser wouldn't care or mind buying the old model Prado/LC with a relatively new or latest facelift.
Facelift of the said SUVs can be quite expensive, they can actually add quite a bit of value to the car.
If you have an SUV that you want to facelift, you can go right ahead and do it. Customs must be aware that the SUVs of the same generation can have newer facelifts.
