That is the funny part. The archive site does have a date (in Polish) but the current site doesn't. I just harvested all of it:I see no date or numbering system
2000X,"011110041",allegro.pl
441,"014081479",allegro.pl
5000A,219090524,allegro.pl
5000A,229100458,allegro.pl
5050,"026071604",allegro.pl
661,"024021643",allegro.pl
7000,221078680,allegro.pl
771,"014011462",allegro.pl
A-550,507110340,allegro.pl
A-5,860121584,allegro.pl
A-M7,572070002,allegro.pl
R-410,664083986,allegro.pl
AU-217,857100111,allegro.pl
AU-317,838080707,allegro.pl
AU-417,229021661,allegro.pl
AU-555A,830060612,allegro.pl
AU-555A,833070141,allegro.pl
AU-9900,215120756,allegro.pl,JDM
TU-9900,835110062,allegro.pl,JDM
AU-999,"021080144",allegro.pl
AU-alpha707,617034882,allegro.pl,JDM,T-tag
AU-alpha907MR,606030057,allegro.pl,JDM,T-tag
AU-alpha907XR,607070076,allegro.pl,JDM,T-tag
AU-D607FEXTRA,822061141,allegro.pl,JDM,T-tag
AU-G77X,635050418,allegro.pl
AU-X1111MOS_VINTAGE,611037065,allegro.pl,JDM,T-tag
AU-X201,507111109,allegro.pl
AU-X301i,530090413,allegro.pl
TU-X301i,628070820,allegro.pl
AU-X417R,126050751,allegro.pl
AU-X701,607020032,allegro.pl
BA-2000,246110101,allegro.pl,JDM,T-tag
Blaupunkt_PT-3690,609048908,allegro.pl
Blaupunkt_PT-3690,628107961,allegro.pl
C-1000,508051019,allegro.pl
T-1000L,508040434,allegro.pl
D-3000WR,328051699,allegro.pl
CD-370,203198009777,allegro.pl
CD-V1000,337071548,allegro.pl
CD-V1000,210232000964,allegro.pl
T-1000L,511011172,allegro.pl
A-1000,531010713,allegro.pl
CD-X105,549102957,allegro.pl
CD-X311ii,203998005363,allegro.pl
CR-M7,211120104,allegro.pl
D-1000W,429011863,allegro.pl
T-1000L,509010174,allegro.pl
A-2000,530070099,allegro.pl
D-590R,666014244,allegro.pl
D-70BW,627059370,allegro.pl
D-W11,617129694,allegro.pl
D-W11,600010850,allegro.pl
D-X301i,328090050,allegro.pl
G-971,819110016,allegro.pl
G-M77,613094897,allegro.pl
D-X311WR,570120271,allegro.pl
CD-X311ii,203698000502,allegro.pl
RZ-3500,510120862,allegro.pl
D-X311WR,570102626,allegro.pl
CD-X105,549090005,allegro.pl
RZ-3500,500110258,allegro.pl
P-D15,336062779,allegro.pl
P-L50,312110210,allegro.pl
QRX-7001,244100304,allegro.pl
R-410,664084010,allegro.pl
R-50,859070848,allegro.pl
R-50,859071725,allegro.pl
R-70,870010750,allegro.pl
RZ-1000,519070828,allegro.pl
RZ-1500,14403004027,allegro.pl
RZ-1500,12003002524,allegro.pl
RZ-3000,519110467,allegro.pl
RZ-3500,21503011853,allegro.pl
RZ-3500,12003007061,allegro.pl
RZ-6100AV,60300138,allegro.pl
SC-1110,247110503,allegro.pl
SC-1330,250010811,allegro.pl
SC-1330,239060767,allegro.pl
SR-222,316110497,allegro.pl
SR-222mkv,315100807,allegro.pl
SR-222mkv,315071713,allegro.pl
SR-525,326061674,allegro.pl
SR-B200,499020081,allegro.pl
S-X900,628033795,allegro.pl
S-X900,618057185,allegro.pl
T-1000,508013268,allegro.pl
T-60,840051618,allegro.pl
TA-300,214100728,allegro.pl
TU-3900,847020543,allegro.pl
TU-666,211010441,allegro.pl
TU-9900,848030229,allegro.pl
TU-9900,847120139,allegro.pl
TU-999,232020218,allegro.pl
TU-217,848103011,allegro.pl
AU-217,828060763,allegro.pl
TU-X317,223498003451,allegro.pl
XP-99,316101541,allegro.pl
XP-99,315102654,allegro.pl
Note that the Blaupunkt PT-3690 are rebadged TU-X301iL and have a bona fide Sansui serial.
The archive site is WIP. Will continue from December 2023. I have harvested the serials for that month but have not processed them.
Fun fact: did find a few serials that were in my own database (Marktplaats cs). An AU-X1 that had been listed on Feebay. And a G-3k and 5k.

