There WAS a torque converter break in period in the PCM and TCM but it wasnt even in the LX or LC cars. Even then, they took it out of the cars that did have it. There really isnt anything in the PCM for a break in. You might feel a tad bit more power once over 5-6k miles but not much.
Other than the rev-limiter, full power is available from the get-go for better or worse.
For as many that have been conservative during break-in (modest acceleration, varying speed, for 500m, etc), there have been just as many that drove them like we stole them with little noticeable ramifications.
I have a relative that works at Dodge (in a different division) that said he talked to the engineers and it was true. Personally, I can not say whether or not it's true, but I can tell you that right at about 1,000 miles on the odometer, mine had definitely seemed like it had an extra cylinder or 2 of power. Coincidence? Like I said, I can't say other than what I experienced.