I have tested a spare charcoal canister and throttle body. I can't make a real determination on the throttle body since it's removed from the intake and the back of the port is open, but the port enters a channel that runs around the perimeter of the venturi to the top where the Holley logo is located. It appears that it connects to a channel that then runs down the opposite perimeter of the venturi and connects to the other port on the bottom. This would provide a vacuum indirectly from the charcoal canister.
The throttle body port nearest the firewall is the one that attaches to the canister via the metal lines on the trunk wall. The port nearest the distributor and idle control valve connects to the EGR solenoid. The other line from the solenoid connects to the EGR valve.
In testing the canister, I find that the nipple on the very top of the canister will operate the valve in the canister. I can hear it click as vacuum or pressure is applied and released. The other small nipple does not seem to flow with either vacuum or pressure and may be dependant upon the position of the valve. I can't apply a vacuum and pressure to both at the same time. The larger nipple goes to a metal line on the fender wall and transitions directly to the fuel tank.
I have 2 or 3 sets of good plastic lines but I wouldn't dare try to ship them. I guess the best thing to do if you find there is a need to replace them is to order a set of stainless lines from Rodney Dickman. Pricey, but they will forever solve the problem and they are a much better fit than lines sold by some other vendors. Previously, they were around $150 but I see he's reduced the price.
http://rodneydickman.com/product_info.php?products_id=86