The gold plated Alpas were strictly for the very rich collectors, don't know how may were plated, enough that they show up once in blue moon on various auction sites. Others were likely made by hobbyists or artists who turn everyday objects into "works of art."
someone found all the paperwork in a swiss office so you can see how many of each model in each colour and any special bespoke cameras were made - like half frame models or whatever.
it was all reprinted in alpa complete collectors guide book but my copy is in storage - however you can see exactly how many of the very flamboyant gold ones were made in the book.
however, the gold ones can be a bit dodgy as when alpa went bust, the spare gold top plates etc ended up on secondary market so people converted normal alpas into gold ones - so there are more gold ones than listed.
why i know all that useless garbage i dont know but i do