I apoligize if this is an exhausted topic...I called my LBS and asked about a SS conversion and said I would have to just buy a new rear wheel?

The bike is a 74' Schwinn Sprint. Normal ten speed setup. Of course i would like to build up a nice fixed gear, but its gonna be my winter/utility bike. I was planning on using everything stock. Can I get a true fixed gear conversion for it? Or is my LBS trying to sell me what i don't need? Thanks