The holes are blind, no thread sealer required. Are you using RTV? I usually put a little dab/smear where the timing cover meets the oil pan rail, same for where the rear main seal meets the oil pan rail. I've been using Superformance gaskets and they're really nice.

For the record I've never had an issue with a leaky oil pan on a B/RB engine, so not sure where the "they all do that" comments are coming from.

Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street