I'll bet the execution plan for both is the same.
It's a messy way to write procedures, at least for really simple things like this, but it's not going to add a lot of overhead to the query. Not for this simple one anyway.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning