It doesn't say but I have always assumed so. I do know for a fact that Paul was. His teacher was Gamaliel (mentioned twice in Acts) who was the grandson of Hillel, for whom that school (Beit Hillel) was named. Beit Hillel was known to teach spirit of the Law and Beit Shammai the letter of the Law. The difference? The spirit of the law considers the intent, the depth, the heart behind the letters. For example... Yeshua said that to even look and lust in the heart at a woman is to have already committed adultery... the commandment was broken in essence, in the intent behind the letter. He did the same when he said that to hate your brother is to murder him (paraphrased). Once hate entered the heart, you might as well taken a pistol and fired. Neither example negates the physical... it is still a sin to kill or sleep with a woman outside of marriage... but to break the command one doesn't even have to get as far as the physical.
His true point Grip... wasn't to show us that it is actually harder to live by the Spirit (it is) but that we need God to circumcise our minds and hearts, fully write His instructions so that we can't ever sin. Until that day brother... we do the best we can.
Incidentally... the Acts 15 letter is really the reversing of a decision that happened 50 years earlier when Shammai's position was accepted as halacha (Jewish law) over Hillel's in a debate they had on what was expected of a proselyte.