It works and doesn't at the same time.

I don’t think any mosasaur skin impressions have preserved anything like this.

Mosasaur skin impressions (from what I know), show small diamond shaped scales, unlike the skin of the earless monitor lizard, but I guess it's possible in some species, considering Mosasaurs make a up a whole family.

Probably but it wouldn't be very hydrodynamic.

Inefficient in water