To recognize if Gaggia is Classic EVO Pro 2023 (aluminum boiler) or Classic Pro E24 (brass boiler) you need to check 12N number on product label (https://www.gaggia.com/product-search/). Number is like 886948111020. If last two digits are 20 (like in my example) then this is E24 (brass boiler), but if it is 10 than it is EVO 2023 (aluminum boiler). The two digits after 869481 are in forming you about color of your Gaggia e.g 11 is for Inox and 12 is for red one. See https://www.gaggia.com/product-search/