The original sentences are mostly correct, but there's a slight issue with clarity in the second sentence. It would be better to clarify what "either" refers to, and you could improve the flow of the sentences.
Here’s a corrected version and a rephrased version:
**Corrected Version:**
"Mine was a Samsung Duos. It was a gift from my uncle, perhaps because I achieved a distinction in my junior WAEC examination."
**Rephrased Version:**
"I had a


