Wikipedia list the D4 as a four door touring sedan and the D5 as a two door roadster. Is this correct? Did other years use the two porthole windows in the rear on the touring sedan??

Wikipedia is not always 100% correct but better than others. The model D5 is a "five passenger touring car" from the factory brochure. It does have four doors and a fabric top. The D4 is described in the same brochure as a "four passenger roadster". It is commonly referred to as a "Chummy" roadster with its "round the hearth" seating. It also has a fabric top.

Also was the Touring with the V8 in 1918 the only year that the round porthole windows were used? Just curious as at one time I saw a photo of my grandfather at a family gathering and in the background was a tourer with the porthole windows. He had many jobs in his life and one was being a chauffeur where he drove a Pierce-Arrow, but his personal choice was Chevrolet.

Oops!! I mistyped the numbers. Sorry but I will edit the post to make the correction. So Steve now your post doesn't appear to be appropriate. My mistake and then correction did it to it.

I have edited my post . Thanks for the info.