My advice is to be aware of it without being paranoid and thinking you have africanized bees just because the girls were testy on a couple of inspections.
In my case, they started out more aggressive than my first hive but only by a small margin. As their numbers built up, so did their aggressiveness so it was a gradual increase. As it got worse, I could not longer deny it and finally re-queened and bought my queen from a non-AHB area. At the peak this is what I was dealing with just so you know:
1. When I smoked the hive, the buzzing increased dramatically and the guard bees would fly out of the hive at me.
2. Just lifting the top cover I would get 3 or 4 stings through my gloves (canvas gloves - got better gloves after that)
3. After even a minimal inspection a battalion of guard bees would follow me all the way to the house, repeatedly butting me and I was unable to come into the house for 30-40 minutes w/o bringing in 20-30 bees. In July in the South I thought I was going to pass out from the heat in my bee suit. My other hive might send 1 or 2 with me to my back door, then give up and go home. One time I couldn't stand it any longer and came in to the utility room anyway and discovered that once they hit the 74 degree A/C air they immediately calmed down and I was able to swat them w/o them getting into the rest of the house. My husband helped swat w/o a suit and did not get stung.
4. Finding the queen was an amazing experience. I was fully armoured up with heavy gloves and a double layer of clothes so I did not get a single sting, but I was in a tornado of angry bees and the sight and sound sensations were something else!
5. As soon as the queen was smushed my problems with this hive were over. I waited 24 hours to introduce the new queen and I had no problems opening up the hive and putting her in, or taking the empty cage out a few days later. They were in emergency-survival mode to pay much attention to me.
You need to do what makes you feel comfortable and able to sleep at night. I am just relating my own experience in case you have to deal with it down the road. I understand now why they were interested in the genetics - that hive built up amazingly fast - they just couldn't breed out the aggressiveness and keep the ability to build up quickly.