Rain Tower - Fence post Gray inside and White outside

Hey everyone,

I am starting to pull together the parts for my own rain tower and an NFT rail. Thanks for all the great videos!!!

I order the fence post from Home Depot which arrived today. In all the videos I have seen the posts look white (the same color) on both the inside and outside.  The two I received were gray/off white on the inside as if the white on the outside is just a coating over a gray vinyl post. Is this normal?

4 in. x 4 in. x 6 ft. White Vinyl Fence Post

Model #  195168
Internet/Catalog SKU# 205885449

Also, This is the 4 inch post. After I held my 3 inch pot up to it; I think I am going to upgrade everything to the 5 inch so that the holes are not so close to the edge.

Here is a picture of the end, if you look at the edge you will see the 2 different colors.