Danny,
If you mean the repair data plate approx 3 inches square, normally on passenger side of chassis near cab, then the top details are the post-1948 army reg. number, but I suspect it may not be XX, but more likely YX. Is this a QLR chassis? If the other number is also on the chassis, prefixed QLC, QLD, QLR, etc, then it could be a 1944 build as 36122 falls in that year of production. You may able to trace the post1948 number through the key cards at Deepcut, that will tell you contract details.