The small four cylinder Continentals used cotter keys in the rod bolts. Whenever I opened one up, the cotters were laying in the sump, but the nuts were firm, at torque. Without thread locker.The relevant bit in this great video starts ay 13.8 minutes and then sealant at around 17 minutes.
I use an engine rebuilder who has been building alfa 105 series race engines for 40 years. He is OK with the cigarettes, but bins the lock tabs. His argument is if you have used thread locker and torqued correctly these are unnecessary. A lock tab will only stop an already loosened nut falling off, if the nut is loose its already too late for the engine. He's not had a failure in 40 years due to leaving out the lock tabs.