I just picked up a beautiful bronze green Supercourse with all the original components (cottered crank, Brooks saddle, etc).

The bike looks exactly like this:

I know absolutely nothing about repairs but took it in to my local shop to see if they can restore it for me. The guy there said that the bike has some old proprietary tire size and that I'd have to get a new wheel set to make it work. Is that right? From what I can tell, this is a 1973-5ish bike and should have 27 X 1/4" alloy wheels. Am I getting hosed?

Thanks for your help.