That does not sound good. The oil cooler isn't doing much in the type of stop-and-go situation you described, however, I'm still surprised that the temp got as high as it did. I took an Experienced Rider's Course weekend before last when the temps here were in the mid-80's. During some of the excercises (all of which were slow-moving and required you to wait in line with the bike idling for extended periods) I checked the oil temp on my LCD dipstick and the highest reading I got was 250. I figured the bike would go into the heat management mode at any time, but it never did.
At the very least, I would change the oil if I were you and I would also discuss what happened with a very knowledgeable service tech or service manager. Chances are nothing is wrong if the bike is running fine now and there doesn't seem to be any new noises, etc., but it wouldn't hurt to see what they say. Undoubtedly, you are not the first one this has happened to. Maybe with a SEEG, but not an H-D.