You can test it several different ways. Remove the air cleaner top, depress the acc. pedal, and note that the choke flap should be completely closed. Have someone start the car and watch the flap. It should pop open about an 1/8" if the pull-off is working correctly.
Other methods are using a vacuum tester to apply a vacuum or connecting a vacuum hose and sucking on the hose followed by applying the tip of the tongue to the hose. It should hold vacuum. An analogy would sucking on a soda straw with a fingertip on the end of the straw.
This is what the pod looks like if you need one.
The parts guys, knock on wood, should know what that widget is.
The frame rails are hard to say. Often they look worse than they actually are. If they are really bad I don’t see a cheap, inexpensive way out other than having some gussets welded in.
Hope that helps.
Yes, the choke should immediately open slightly when the engine starts. There is certainly 1 choke pull-off on the carburator at the rear of the passenger side. If there is not a second pull-off at the front of the passenger side get one and install it. use a “Y” to tap into the vacuum line immediatley adjacent to the pull-off when installed. There are holes drilled and tapped just waiting for the device to be installed. There is no linkage to attach and it is adjusted with a nut driver, hopefully the directions are sufficient. If the pull-off is there, it sounds as though it is not working and needs replacement-see above.