No. It was remiss of them not to tighten the oil filter housing if that's what you meant - or did you mean the oil FILLER CAP?
If it was the oil filter then simply tighten it to the correct torque and as long as the leak stops then fine.
If the filler cap then simply tighten it to the correct position by hand and you should be fine.
I doubt if you'll have lost a lot of oil before you noticed the leak, but do check the oil level using the dipstick with the car on level ground and after the engine has been stopped for 5 minutes. Top it up if necessary but do NOT overfill it.
ChicksFan
May 2012