I got that info by cross referencing decks and models on the Cub site and some of the sites advertising here.
https://www.cubcadet.com/en_US/ridin...A40013100.html
eg;
OEM 50" STAMPED DECK 19A40013100 603-04813 903-04813
CUB CADET XT3-GS, XT3-GE, XT3-GSE, GTX2100, GT2100, GT2000