Take note! here is what I hear are the most collectible conjunto button accordions these days:
"Most collectable at the moment: Mint 1970's or 80's Gabbanelli 3 switch with old lettering, grille and engraving.. ( Los Cadetes style ); Black 60's Corona II in mint condition ( raised grille with flat buttons and white bellows with brown corners ); Corona IIIR in metalflake or odd keys; Hohner Erica in black or blue marble. . . the list goes on."