If it weighs 32.75 I will say it is most likely from the 3/29/96 order of 12 bats that weighed 32oz. Bat weight can fluctuate over time due to temp and humidity. Like you said, if it has pine tar on it then it did add some weight.

I can't rule the bat out from being one of the 24 from January or February but when a bat does change weight it usually loses weight and does not gain unless its kept in a damp area.