I noticed what appeared to be oil leaking from the housing where the drive shaft connects to the rear wheel. I have a 2006 Honda Shadow Aero.

Honda Shadow Aero 750 Motorcycle Test ' Motorcycle Cruiser

www.motorcyclecruiser.com/honda-shadow-aero-750-motorcycle-test
Apr 27, 2009 - Honda's all-new middleweight V-twin motorcycle finally brings shaft drive to Honda's 750 V-twin.

I think you are quite correct. The neoprene rubber oil seals like to be warm to grab the bearing properly.
Keep your eye on it though.

If your bike were a 1959 650cc Triumph Thunderbird, like mine, I would have said you have run out of oil!

Ride safely.

Get it checked by a M/C garage as it may be expensive if it fails.

You do not have to remove the final drive , the wheel is resting on a spline shaft. Center stand the motorcycle or lift the rear wheel, remove the axle bolt, knock out the spacer, and slide the brake panel out of the way. Now the wheel is resting only on a splined shaft. Grab the wheel and gently slide it away from the final drive ( off the splined shaft ) and roll it out the back of the wheel well. When replacing the wheel be sure to get some MOLY60 paste from the Honda dealer and grease the spline before putting the wheel back on.

remove brake tension nut, remove bolt on frame bar, loosen bolts on shaft clamp after removing nut on shaft then knock shaft out . must have bike on jack to clear ground when working tire loose .

oil seal gone on the shaft cheap to buy but a bugger to get off as you have to strip the drive off andthen pop the old seal off with a screw driver then slide it of and next ge the new seal dap some oil inside then slide into place and rebuild also top up oil in engine