It looks discolored and also looks like someone may have replaced the glass face and done a very lousy job with the aluminum glass retainer ring. These are form fitted over the glass and aren't meant to have the glass replaced. It can be done but is very difficult and it looks like this one may be ruined?? Can't tell without better pictures and the saran wrap removed.
I good shape, the thermometer is worth from $200 to $300 with some variations bringing slightly higher.
I would expect this one to bring $100 or less but again would have a better idea with better pictures.
