What are these electrolytic capacitors?
I would say that these are indeed non-polarized caps. You would want to replace them with similar capacitors. Do NOT replace them with ceramic caps. 

Ceramic caps are great for many purposes but not in the audio path. Among other problems, they suffer from piezo electric sensitivity and their value can vary greatly depending on the magnitude of the DC voltage across them. 

Digikey and Mouser have suitable replacements available.