JayMac - the M52 gasket has a steel rim that spaces the rubber properly and allows you to torque the bolts down correctly. If you're going to go to the trouble of taking the oil pan off, then I would get yourself a new gasket and put it in - they only cost about $30 or so.
Even if you have to cut it and join it using gasket sealant, you'll still get a better result than trying to just use sealant.
It's 6 months since I did the pan in mine and it's still bone dry even where the join is. The cut and join method is a winner as long as you do it right.
Do you know how fast your E39 is?