There are two basic things to check to see if a stock AC B/C hydraulic pump can be easily added to your tractor. First you must have a pto housing that has the capability to mount the pump. You can determine that by the presence of a rectangular blocking plate on the right hand side of the pto housing, looking from the rear of the tractor. The pate is attached by two bolts plus two studs. If you have that plate, then the pto housing has the provision for attaching the pump. If you don't have that plate, then forget it - you would need to replace the pto housing with a proper one in order to mount the stock pump. Secondly, you need to have a pto shaft that has the two cam lobes on it to drive the pump. If you have the rectangular blocking plate, it is likely you have the shaft with the lobes. However, to be sure, you can drain the housing, remove the blocking plate and verify that the shaft has the two lobes. I have a 1942 B that I added a hydraulic pump to a couple of years ago. I got the pump off ebay. Fortunately for me, my pto housing had the ability to mount the pump and the pto shaft had the cam lobes, although the tractor never had a hydraulic pump on it.
Your tractor serial number would be of no use in determining if you can mount a pump. The early pto housings did not have the ability to mount a pump and the easy interchange of parts over the years means you have to actually physically verify what you have in order to decide anything. If you do add a pump, be sure to drain the entire transmission, differential and pto combination - three places. If no pump was in place before, you most likely have heavy oil in the combination sump. You will need to use SAE 20 weight oil of the more modern trans/hyd fluid (SAE10) when adding a pump. You would also need to flush the system good before adding the light weight oil.