This is a Cornet I believe. Are there serial numbers? Those are what is used to date. I'll go look for a site that lists them.
ETA: Having trouble finding Pinkert.... Can you get a clear pic of the engravings? As far as the value goes, the more you can find out the better off you will be. Hubby has been looking for one for quite awhile so I have "antique cornet" saved as an eBay search. There are new (old) ones up everyday it seems. They run from under $50 to many hundreds. The most desirable (aside from Bach's) seem to be silver with a Sheppard's Crook. Also, any dents, repairs, etc will greatly affect value.
If we can determine the date on yours, value should be easy via eBay. That said, you may do better with a local consignment.