Gary, any luck finding the piece you were looking for? I'm in a similar situation, putting the standing rigging on my parents' W32 back together and I'm missing the fitting that sits inside the cap. Here is what our gooseneck and boom look like. 

Norm Rhines wrote:

Eric:

Your Fitting shown is not so much Lefiel;  So It is a bit easier to make the part.

You can do it with a drill, small bench or angle grinder, and a tap.

Find the distance from the back of the end cap (inside the boom) to the front and it's diameter.

Buy a ss bolt 3/4" longer than this, and at the correct dim. (you can use washers to take up, up to 1/2")

Measure the space between the sides of your fitting shown in the picture then buy a 1 1/2" wide "Flat Bar" pc of 304 SS. that is as thick as the space between the sides on the fitting shown in your photo (3/4" or 1"?),  drill a hole so a pin fits through it and have the pc so it sticks out the back edge of the fitting in the picture 3/4" to 1" beyond the back edge of the fitting, then drill and tap the back edge of the ss for the bolt. (grind as needed for looks) You may want to put a plastic washer between the end of the boom and the new ss pc.

Hope this helps

Norm

Thanks for the advice! Going to give it a shot this weekend and see how it works.