That's not part of installing the starter but if youre leaking oil and don't want it to end up in the bell housing or in the starter you could. But it would take a ton of oil and is not likely at all that enough oil would fill the bottom of the bellhousing and spin oil everywhere on your clutch disc which you do not want. The bottom of the bellhousing isn't even sealed. Oil could seep in the bellhousing from the top , like the valve cover, but i've had some dandy leaks before and never had an issue with my clutch from the clutch disc being contaminated. I think you're alright. But I got off track. That's not a source of leakage.
1984 jeep cj7, 258 I6, rebuilt T176,rebuilt Dana 300, amc 20 , dana 30, 4.10's Trac-lok in rear , 4.10's detroit soft locker in dana 30, 2.5 inch bds suspension lift, 1 inch polyurethan body mount lift. Line ex. weber carburetor. factory tach. factory clock ,oem replacement speedomter cluster, and oil pressure gauge, factory volt gauge.