SP, Thats the packing for the rear main cap. The oil seal is bolted to that, using the shellac, but dosen't involve the felt packing.
The two halves of the oil seal need to be aligned as the engine is being rebuilt, while the crank is still out.
The rear main bearing cap gets dry fit and torqued, then there is an alignment tool that fits in the bearing hole and simulates the crank, albeit slightly oversized from the actual crank, then you apply the shellac and fit the two halves of the "seal" in place and torque them down. then the tool can be removed, the cap removed, and the crank fitted and then reassembled.
As long as the "seal" halves aren't loosened on what they are bolted to they will be aligned when the bearing cap is replaced.
With the engine in place there is no way to get to the bolts holding the seal halves in place, they are hidden behind the flywheel.
And without the alignment tool any adjustment is likley to make things worse.
These things leak quite a bit, even when everything is right. The cotter pin in the hole in the bottom of the bellhousing is to keep the hole from plugging up and letting the bellhousing fill with oil.
A very small puddle(several drops) under the car after it's sat a while is perfectly normal.
the "seal" only works when the engine is running. when it stops, it will leak.
Hope this helps