I wouldn't necessarily agree with you, as long as @AndrewM keeps himself kinda low-profile and humble. I mean, if he just says that he got X internship with Y institution that mainly deals with 1, 2 and 3, I think it wouldn't make him seem desperate. Rather, they may want to evaluate it positively in terms of candidate's good foresight together with the great opportunity coming up for him. Different reaction would be caused if he claimed the duties he'll be assigned to or the skills he'll gain, given that, as you said, he hasn't already completed the internship in question. However, I believe it is too late anyway for turning things around: les jeux sont faits.