I doubt it. It was in order to make the phone thin.I wonder if Apple's decision to put the antenna on the outside had anything to do with the Nokia antenna configurations patent dispute. It could have been a preemptive decision to avoid further litigation/having to pay a hefty licensing fee.
If you've followed the Keynotes over the last few years you'll know that Steve isn't the only one getting thinner, but the products as well and he always make a big deal about it (pictures showing comparisons with the previous model from the side, etc). They've made 'thin' into such a big deal that people take for granted that each model will be thinner than the last, to the point where it would make headlines if it wasn't, and the new product would immediately be ridiculed as the iBrick, the iBurger, the FatPhone etc.
So... they had the 3GS which was already jam packed and now they were faced with having to shoehorn a much larger battery, a gyroscope, a front facing cam, LED flash etc into the phone and I'm sure 64 GB was on the drawing table at some point as well. Also, they wanted to solve the long standing issue with radio transparency dictating which material they put on the back of the phone. The previous designs were compromises (aluminum with a black plastic window wasn't ideal, and the full plastic back was kinda cheapo if people were used to aluminum.
Then someone had an Eureka moment and figured that if you put the antenna in the metal band around the edges, you kill two birds with one stone: You're free to put any material on the back because radio transparency is a non issue, plus you make more room on the inside with the internal antennas eliminated. There was just one catch, one that didn't go down so well with users as it turned out.