Can anyone tell me if the arch kit should have a double sided tape or something along the edge of the kit. There looks to be a lip where this should be.

I am about to fit mine and was going to put a thin strip of double white tape (Cars white) to help make a neat fitment. It does look like someone used some white sealant in the past.

 

Mate I’m no expert on this but I will double side tape my own when it’s at that stage , you want is tight and even all around
steve

 

Sure there's a 3m product specifically for this purpose that I saw on ebay long past and should have saved the link as I'll soon need some myself. Any decent bodyshop should be able to help you locate some.

 

On the inside of the wing at bang on central there is steel flange / insert . Your arch liners have an opening on the outer lip that wing flange is the insert and sits and holds the arch liner .