Suspicious white spot on first damsel fish -- ich?

[TexasDefender]

After cycling my new 29 gallon saltwater tank for a month and a half (with 50 lb. true live sand and 50 lb. of coral fossil rocks), I went to Polly's Pets in Universal City this evening (11/22/08) and bought 3 damsels and a cleaner shrimp. After fixing my PH to 8.2 (ammonia, nitrates and nitrates all at 0, salinity at 1.024 at 79 degrees), and floating the bags for a good half hour, I took out the bags and set my first ever saltwater pets free to roam.

Within the first few minutes I noticed that one intense blue damsel has a white patch on its left shoulder (see pictures). My fear is ich, but I also wonder if it’s just color variations.imperfections, in which case I want to keep Old Blue. I am not sure whether to take the blue damsel back to the pet store. I'm just getting going, and I don't know if I should try to play Florence Nightingale when I don't have a clue what I'm doing yet. If I have an ichy fish, I want to protect my tank and my other 2 fish and shrimp from infection. I also want to steer clear of copper if possible, because I am planning to introduce coral within a few months, and I believe copper kills coral.

What do you recommend? If I don't get any responses by about 1 PM Sunday, I will probably try to take Old Blue back to the pet store for an exchange.

Thanks in advance for your input.