If the TV Series you are looking at is from Magnavision (Sony, Paramount, Universal), chances are it's All Region (Region 0) if it's locally pressed (see thread on whether disc is DVD 5 or DVD9).
If it's from Warner (WB, HBO) or Viva (ABC, Disney, Fox), they are Region 3 locked.
Imported TV Series from Magnavision are also Region 3 locked, but Magnavision releases very few (if any) imported TV series these days...
As said Region 1 discs from local retailers are rare, unless the store you are saying, deals with Imports and is a store that caters to high-end home theater crowd...