You're on the right track. The regulator in the spider can go bad and leak fuel into the intake, the poppets could be loose and leaking fuel into the intake. Also the fuel lines running to the spider could be bad and leaking as well. The pressure test will tell you if you need to take the intake manifold off to find the cause.
The spiders are expensive. I think I paid $250 for mine on ebay. But that was for a AC Delco part too.