Antiques? I need price lists of my old Imperial Chicago Baby Grand accordion. I wonder if this is antique?

I can not find anything about the accordion I got by the name of "Imperial Chicago Baby Grand." Similar ones run up to $3,500. Is there some like a Blue Book of accordion makes, years, prices, and worth? Every web sight I looked at so far mentions "imperial" but no Baby Grand, or what model I have. The closest thing I've found was PBS Antiques Road Show Web Sight, that shows accordion videos. But, I have not found the particular model I have anywhere. This tells me that it might be a really rare item. Any help would be appreciated.Even libraries don't show accordion pricing info on the search engines.