Thanks for the replies.
Since I need to add a toping lift and I'd probably pay someone to go aloft to run the line to the mast I may go ahead and install a rigid boom vang since the price doesn't seem too steep and I've heard good things about Garhauer.
I'm not sure about the gooseneck. I believe it does not slide but I could be wrong. I don't think the prior owners upgraded any of the standing rigging for improved performance or safety. But I'll check and let you know. Why did you ask? I'm guessing it may have to do with somehow fixing the gooseneck in place if I have the type which slides?