A few years back I bought a used Turbo Action 17676 valve body at the Nats for my 727. I finally will be getting around to installing it and was wondering, is there anything complicated about installing a valve body or anything I should be aware of? When I got it, all I got was the valve body itself. Looking at this particular valve body on the Summit website it shows a spring and two gaskets which I didn't get with it. What is the spring for and do I have to have it?

https://www.summitracing.com/parts/tac-17676