No the probe is inside the egg box and to double check it I also used my temp gun and they are pretty much the same only 2 tenth of a degree (if I am saying that right, one was 88.4 the other was 88.6)
We double check ours with the temp gun too . Looking at a poll posted on this site, it looks like most people incubate at 88.5-88.9 Some people report having bigger, healthier babies when incubating at cooler temps, but I haven't looked too much into it.