If you do a search you will find a lot of threads about this although there hasn't been one for sometime.
Dots are like a religion. Some people couldn't care less. Some are convinced that the only true dottiness is one at the 7th. Others reckon that lots of dots is only true path. Exception, "all uneven" seems to be a little too much dottiness. Never came across that.
The main denominations are:
Agnostic - couldn't care less. (common)
5th,7th 9th 12th. (common)
5th,7th 9th 12th. (15th rare) (17th rare )
Believers in one dot or no dot, claim that anyone requiring more are wimps who will never be able to master the holy instrument whereas the lots of dot believes cannot understand how people cannot see how obvious it is that dottiness is the true path to musicality.
All of these dotty factions agree, however, that dots or markers top on the fretboards are only for cowboys or worse, pop musicians.
If, as a believer in dottiness, you are unfortunate enough to receive an undotty guitar it is perfectly acceptable to use stickon paper dots or tipped (white-out) or any other markers to imbue the guitar with temporary dottiness.
Dot material is in principle not of interest to the dotty denominations. Commonest material is likely to be white or cream plastic. Mother of pearl is popular too. Use of a precious or semi-precious material is not unknown but rare.