wicked air rifles flex .30

I'd say anybody who works on PCP's could do it, especially if they have a good assortment of O rings on hand. Running down O rings for a one off repair is usually not profitable for most airgunsmiths. For common decency Wicked should provide a list of such things including diagrams and specifications for sites like this to put in their documents section (I know they are out of business but would be a kindness to former customers).