Perhaps, but that's just one theory. I bought my G35 coupe in the first six months they were available and most dealerships were tacking on a "market adjustment" of $2-3K (though I didn't pay one). In that case dealers were simply taking advantage of high demand and low initial supply. The car was a huge hit for Infiniti and they went on to sell 2-4K per month (during which the adjustment was dropped).

I think your argument would be more compelling if Isuzu was applying that markup in 2000 and 2001. By all accounts I've read there was ample demand in 1999, which I think makes a market adjustment an equally (or perhaps even more) likely explanation.