you wouldn't need to seal the tile. but you may want to seal the grout. it depends on the type of grout he is using. you would need to ask him about the grout and whether it is stain resistant.

What joint size is he doing? If it's 1/8th or less he may be using non-sanded grout. Non-sanded grout uses polymers to better attach to the tile. On polished tile that's not a problem. But a lot of the wood-look porcelain tile has a flat surface...just slightly rough to the touch. If that's what you have just know that cleaning the grout haze will be BRUTAL. Those polymers in the grout will keep the haze on the tile no matter how many times you clean them. I'm in the cleaning stage now on 1,000 sq ft and have mopped the tiles more than 15 times...still hazy. I've used water with an all purpose cleanser, multiple expensive cleaners designed specifically to remove grout haze and an 8:1 solution of white vinegar and water. They all worked about the same. Most of it came off after about 6 moppings but then progress was very, very slow. Until today that is. Read a post from someone that said a 1 to 1 or even 100% white vinegar solution is completely safe and much more effective. Tried it just now and the tiles are totally clean after 2 passes.

Regarding sealing, most folks say dont seal wood look porcelain tiles because they are glazed and dont need it...to just seal the grout. But my tiles are a little duller than I would like so i've done some experimenting and found that some sealers will give you allow you to get the look you want: gloss, satin or flat. I really want satin and I want the tile sealed anyway because the slight roughness of the finish makes they WAY harder to sweep or vacuum. I'm going to try a few of them on spare tiles to make my final decision.

Update to my earlier comment...

The gourt haze never came off my tiles. Lesson learned: You cannot use non-sanded grout on wood-look porcelain tile...or any tile that is not highly-polished. The polymers in the grout will stick to the surface of the tile if its anything other than highly polished.

I used norrmal, sanded grout in the basement on the same tile and the tile looks the way it should...a low sheen...kinda satin. But I didnt love the 3/8"grout lines...made it look more like tile and less like wood. On the main level I used non-sanded grout because I wanted as narrow of a grout line as possible. Did them at 1/16th.

As I cleaned the excess grout (scores of times over weeks) the polymers stuck to the surface of the tile and made it dull...permanently. The good news is that, after weeks of trying to repair the damage, my neice (a designer) came over and said she loved the fact that are completely without a sheen. Over time I have grown to like it quite a bit myself. So all's well that ends well I guess but sure wish I had known what would happen if use non-sanded grout on wood-look tiles BEFORE I did it!