Not quite the same. OTR Proper means that the conversation is secure and authenticated, as well as deniable. You can also achieve the deniability trait if you

Not quite the same. OTR Proper means that the conversation is secure and authenticated, as well as deniable. You can also achieve the deniability trait if you simply don't secure the conversation. If everything is plaintext then you could claim that any logs have been potentially tampered with. Now, if the conversation is secure but you're not using OTR, then simply "not logging" doesn't really get you much. The other participant could still be logging, manually if they have to.