well, in my experience if you do a b swap and want to keep your p/s you have to get a p/s pump for the engine you are swapping in, Also you will need to replace the p/s pressure line that goes from the top of the pump to the p/s rack with the line for that engine.
for example if you do a gsr swap into a 95 civic you have to use a gsr p/s pump and a p/s pressure line from a gsr also.
Reason being that the d series pump does not mount correctly to the B block, Nor does the d series p/s pressure line hook up to the b series pump.
all in all it's only 2 parts that you have to buy, and usually when you buy an engine for a swap, it comes with the pump, so you would only need the pressure line.