Hi bernie
It's always best to ask, it's only easy if you know the answer, I've found also that the horse chestnuts come out earlier than the sweet chestnuts, and yes the spikes on the sweet chestnuts are to a point hard to pick up/open with bear hands. There are normally three mainly triangular shaped nuts in a husk of the sweet chestnut, the two outer ones bigger than the one in the middle, the best time to gather the sweet ones is about October after some heavy winds, I like to eat them
Raw as well as roasted, when raw you get a nice crunch with an ever so sweet taste, roasted its best to put two or three slits in the shell as they expand and could explode if you don't, on top of your stove/heat source in a small pan, put a drop of brandy in after they come off the heat, very nice, I do look forward the the autumn's harvest. Places you may find sweet chestnut trees are like golf courses, county manors, large estates. Etc,
I like nothing better than being out in the cold wet windy conditions walking with my dog, and coming home and sitting in front of the log burner with a pan of roasted chestnuts and quaffing a glass of last years sloe gin watching Elle on countryfile, Bliss