2. Engraving
Most lock manufacturers use some distinctive markings on the key, such as SC1 and KW1, if your key looks different than the two examples, check out the engravings, or if your keys are marked with a number or letter on them. If your key has KW1, KW10, 6, 65, 66, 5, WR5, or WR3 engraved on the head, it should be the Kwikset. While if the engraved numbers are SC1, 68, or C, it should be the Schlage.
3. Grooves
Lay down your key with the teeth facing up, the Kwikset key should have two grooves while the Schlage only has one.