I've walked up the string of ponds between Hallett and Flattop and recall looking more at Hallet. Flattop is also visible from the Longs boulderfield. The peak is shown to be interesting in its own right in both summer and winter.
Thanks. Yes, Hallet is what catches your eye on the hike to the lakes. Flattop is glimpsed through the trees, and it turns out t be a surprisingly interesting peak.