nice machine, but it's crying out for knobbly tyres and some mud splatterring!!!
seeing it has slicks on it though i assume you are using it for commuting? this worries me! GET A BIG LOCK!!! AND A BIG SNARLING DOG!!!! seriously please!!
with the mag 20 forks, the guys are correct with the needle type pump, but again use the correct type of needle, a normal pump and a football needle is like using a sledge hammer to crack a wallnut if you see what i mean! the air chamber is quite small so using a large barrel pump is not a good idea.
i have some mag 20's myself (in bits at the moment) i found mine on a scrap heap and had them painted, the seals were dead so i phoned tim at tftunedshox he had sourced the correct seals but would only sell them if he serviced the forks aswel (otherwise it wasn't worth his time) they came back working fine. they have since been painted original again and will be going back together soon. so parts can be found if needed.
my old shop in southampton definately has one of the required pumps in their workshop (GA cycles) it won't be for sale though. but my advice would be to find an independant shop as suggested with a history of early rockshox dealings because they will more than likely have a pump to use.
and welcome, soon you'll have it stripped and polished, rebuilt and lovingly cared for! then you'll buy loads of other bikes that you "need" for each and every purpose you can think of!