Is it standard to put insulation under vinyl siding?

We had a man put rooves (roofs?) over our porches and his work was fine. We decided to have him install vinyl siding too. Before we went out of town last week, he was at the house and said his computer was messed up so he was unable to print a contract for the siding. I wrote one myself which was a dumb idea -... show more We had a man put rooves (roofs?) over our porches and his work was fine. We decided to have him install vinyl siding too. Before we went out of town last week, he was at the house and said his computer was messed up so he was unable to print a contract for the siding. I wrote one myself which was a dumb idea - and forget to put in that he would supply and install insulation under the siding...anyway when we got back in town yesterday he had completed over half the job - and it appears to be a type of siding that I didn't choose - and I don't see any insulation...I think I'm covered on the type of siding - although I hate to say..."take all this down and start over" - but my question is - since I forgot to put insulation in the contract - am I stuck without it - or - is it something that is so standard that it would be assumed the insulation would be included in the job?
Update: The houses here that I've seen all have a foam insulation placed on the home before the vinyl siding goes on.

The siding is placed directly over the prior siding (mine is masonite) and it wouldn't matter what insulation is under the prior siding.
Update 2: I chose the siding before I left town - Pearl - D4 Dutch lap - white soffett and white trim on all doors and windows. He showed me two types - there is a kind that looks like wood siding on a house - shingles overlap - and a kind with a flat surface - a dip - a flat surface - a dip ...I told him I wanted the kind... show more I chose the siding before I left town - Pearl - D4 Dutch lap - white soffett and white trim on all doors and windows. He showed me two types - there is a kind that looks like wood siding on a house - shingles overlap - and a kind with a flat surface - a dip - a flat surface - a dip ...I told him I wanted the kind that looked like the wood siding normally looks on a home - and pointed to him the type I wanted - and he said that was "D4 Dutch lap" and I wrote that in the contract. There were 6 of us outside when I wrote the contract and ...I kept asking "is there anything else" and no one spoke up and said insulation...I wrote that he was to furnish all materials and install siding (Pearl D4 Dutch lap... etc).