Was Jimmy Altieri a rat?

Prior to my last post on season 1's top role players, I didn't even think twice that Jimmy was the rat. The crew seemed pretty sure of it: Tony becomes skeptical of Jimmy in the basement when he is released quickly after being pinched and starts asking questions, and Junior agrees with Tony when Jimmy calls a meeting to "go over shit we already discussed."

However, yesterday /u/The1WhoKnocks-WW pointed out that he doesn't think Jimmy was the rat, and instead the whole debacle was to show what lengths Tony would go to to protect his friend Puss. So he fingered Jimmy as the rat and he was killed.

The show doesn't offer much evidence either way, but in season 2, Skip does say to Pussy that all suspicion of Puss as the rat went away when Jimmy Altieri ate the pill for him. IMO, that's the most damning evidence that Jimmy wasn't the rat.

The evidence that he was a rat were the previously mentioned suspicions by Tony and Junior. Also, there was the funeral where Jimmy mentions to Junior that he always thought Junior got it right with Brendan Filone (implication being he was wearing a wire). Also, the FBI agent in charge of the investigation at season 1 bragged to Tony that he was the one who bugged Green Grove. Well, Jimmy tried to get his mother into Green Grove, so maybe he gave that info up?

After thinking about it yesterday, I don't really know if he was or not. What do you think?