I just bought my dinning table. Most of the factory will apply a lamination on top of the marble. You only can see bottom is marble but top is lamination. Of course weather you get grade A or grade B, no difference coz there is lamination. You don't see it.
The difference would the quality and design of the lamination.
If you want to go for non laminated, you will find those in Kopitiam type or those expensive type imported. Those imported type has a beautiful texture marble.
The price should be around 5k above.
Mine get 3k plus with 6 chairs. Saw some going at 2k. But the surface is different on the texture and color as well as the coating.

Those market selling around 3k and below is all laminated one.
Surface looks beautiful but fact is laminated. Go and see the furniture fair you will now.
Those non laminiated will cost you a boom, those imported from ovesea marble.