Hi, John/Doc
They are indeed adjustable but a bit tough to see in the earlier photos. Adjustment is accomplished by moving the eyelets.
Check out the tip weight box. It's a 1/2 inch brass tube, 1 1/4 inches long, closed at one end and fitted with a screw-on cap on the wingtip.
Just unscrew the cap, add or remove lead shot, replace the cap.
Make sense?
Bob Z.