No2Chem's roms get released as basekits that are then turned into true kitchens as they achieve a satisfactory stability level.
Basekits are developer versions of minimal kitchens...they generally are very poorly supported. Unless you know what you're doing, wait for a kitchen.
19588 refers to the build version of WM. In the specific case of 19588, it was a Diamond rom. The 19588 kitchen is the first kitchen to cover mulitple devices (prior kitchens are all device specific). It was released by the PPCkitchen team.
You can find release information for kitchens (not basekits) and OEM packs at
www.ppckitchen.org.