Just a thought here... It may be the same type of Bermuda but from different shipments with one being much fresher cut than the other when it was laid. If the landscaper buys from some certain dealer then that dealer would most likely carry one species of Bermuda grass that he gets from his grower.
Steve

That actually makes perfect sense - so the good old question, it's been a month and I just cut the grass for the first time last weekend, do I need to fertilize it now?

The most oft given advice for my area in DFW is to fertilize at a reduced rate after the second mowing but that applies to my area, not necessarily yours (although Austin shouldn't be an issue)... Additionally, with cooler weather coming on quickly, you have to be careful about a product's nitrogen content because you don't want to stimulate new top growth when colder weather may just come along and kill it, weakening the plants in the process (energy expended with no viable return). A fall fertilization is generally a good thing but applied too late and it doesn't always do what you need it to do. Check with your local experts or local Master Gardeners for suggestions on products and timing.
*Note: if you're an organic gardener/lawn grower type, most organic products can be applied nearly round with good results and without the issues noted above.
Steve

Can you confirm that you have bermuda?

How are you watering the new sod?

Did they roll the sod down?

How high/low did you mow? and does it seem to still be growing?