as i used to have it listed if a leon came with a standard completely open glovebox (normal) to add a cd changer you had to fit either :
1M2 857 095 J 73Y (Black for SE/Cupra)
1M2 857 095 J 6QU (grey for S model)
+ cd changer loom 1M2 971 735
now for a normal NON cd changer type box
1M2 857 095 E supercedes to a G
6QU anthracite (grey) 10/98-11/99
1M2 857 095 J
P21 ecru beige 10/98-11/99
1UQ Persiua Black 10/98-04/01
6QU anthracite 11/99-04/01
73Y blacksea 10/98-04/01
supercedes to a K plus needs 6Q0 959 623 A 01C and both J+K show with cd changer hole sorry
theres loads more as the years go on and trim codes change but all listed as CD changer type
in final there was effectively only one genuine box without the cd changer hump
1M2 857 095 E 6QU anthracite (grey)
1M2 857 095 G 6QU is its newer number but i bet it supercedes again to a box with the hump in it
so although there was one originally i fear that it may no longer be available and even if it is it will only be grey not black and dread to think how many i threw away
cant match any numbers exactly to A3 as they have also quattro and airbag switch options but gotta admit it looks worth investigating