Prioritization of IF-ELSE / TRY-CATCH and First() vs Single()

So, I've been having a little bit of an argument with a fellow coder lately. Specifically: We've been arguing about the proper use of Try / Catch and If / Else as well as First() / Single() in a specific scenario.

Variation #1 - His approach

var items = Search(dto.number); // Returns a List of Objects
if (items.Count = 1)
{
    wPerson = items.First();
}
else
{
    return;
}

Variation #2 - I changed his code to this.

var items = Search(dto.number); // Returns a List of Objects
try
{
    wPerson = items.Single();
}
catch
{
    // Handle exception
    return;
}

We expect the result of var items = Search(dto.number); to always be 1.

The Question: Which changes were nescessary? I am trying to defend my point of view below. Please correct me.

First of all: The Single(). I always try to be as specific as possible and I decided on the following rules:

• First --> Accepts N
• FirstOrDefault --> Accepts 0 and N
• Single --> Accepts 1
• SingleOrDefault --> Accepts 0 and 1

First() may have worked but it wasn't 100% specific, so I considered it wrong since we had an option to be even more specific.

Secondly: Try / Catch vs If / Else. Since I had already changed First() to Single(), I considered the if statement to be redundant. Yes. I know that Try / Catch is less performant than the If statement but we expect to have NOTHING BUT 1 result. And if we get more or less, I expect it to be a mistake and with Try / Catch I'd actually treat it that way.

Am I so off here?