Degsy, NCB is the National Codification Bureau identifier which in the case of 25 indicates Norway, as in SKF Norge A/S, Jerikov 14, Oslo.
DMC is the Domestic Management Code used to aid stores identification preceding the NSN (NATO Stock Number) it was derived from the old VAOS (Vocabulary of Ordnance Stores & Ammunition)
eg if the item was preceded by LV9/BOE it would have been Humber 1-Ton, or LV7/BD then Bedford.
If it was LV6MT7 it would be for bearings that are not unique to one type of B or C vehicle, but if it was LV46MT7 it would have been a bearing for certain A vehicles.
In more recent times the LV has been omitted eg 9/BOE
Andy what is listed as you mention is the "non-significant number" which within a given country is unique.
It only becomes universally unique with the NCB code to form the NIIN (NATO Item Identification Number) which omits the first 4 digits (NSC = NATO Supply Classification). Even without the NSC the item is universally unique. The "non-significant number" is only unique in the vocabulary of one specific country.
Although I much prefer to see a DMC used with the full NSN (NATO Stock Number) it can be argued that there is less tedium when looking in a parts list to identify items by the "non-significant number".