Two Lost Minor Key String Quartets by Mozart?

[Arno]

Dennis,

Is there a link with the set of 6 string quartets by Joseph Schuster? These were found in Padua in an copy writen by Schuster himself. This confirmed that Schuster is the writer of the string quartets C20.01 - C20.04.

K6 remarks (taken from this website): Full score copy (along with C20.02- 20.04) in collection of Fuchs with copies of K155 and K159 received from Salzburg; St.Foix and others believed authentic and from time of K155-160 or K168-173; Einstein believed possibly authentic but not enough proof to place in main portion of K3; in 1957 C20.02 found to be quartet of Joseph Schuster (1748-1832) and attributed all four to Schuster.

Two quartets of the Schuster set are left. These quartets are in g minor and in d minor. I can't check if the incipits match these two lost minor key string quartets. It is pure speculation but mixed someone the Schuster set with authentical Mozart quartets?

Arno