Really sorry bro. I totally messed up. When we have cis dichloro cyclopentane where both Cl are on top or both are at bottom. Flipping is valid and we can say that the two are identical after flipping. But that is because it's meso. Here, 1 and 4 are chiral so flipping is like actually getting enantiomer.
The correct reasoning:
Product 2 and 3 are the same.
Product 1 and 4 are not the same. Rather they are enantiomers.
Hence total number of products are 1, 4 and (2/3)
Diastereomers: 1-2 and 4-2