If all is well I dont see any point taking the sump off.
However if you do decide, then its fairly straight forward to do, if a little messy!
To be honest if its a high miler and you dont know much about its history, I would change the oil pump, while the sumps off, they only cost £25 from ECP and is a doddle to fit. Small price to pay for piece of mind, especially without a baffled sump.
Thats what I've just done anyway!