I have found that it is best to actually use the phone to call the ILCA office. If you can get the right person on the line they can look up the mfr'r of your hull #s (9469 & 4677). They should be able to tell you the builder which, with more research may point to how the builders implemented the mast step.
On the Lightning I owned (#11416, frp by Clark) the mast step was a metal track or channel perhaps 3" wide (wide enough for the mast to fit into) that used bolts to adjust the fwd/aft rake of the mast foot step. The sides of the channel had many different holes for the bolts so it was adjustable, with some fumbling.
You may be able to design a more elegant adjustable setup for the mast step. I'm thinking more along the lines of a main sail traveler car. If you are interested in racing these boats the 1 Class rules are quite specific as to what hardware is allowed, or not. If you are just doing it for fun then have at it.
Your email address has your website in it: Dane F. Jensen Design