If you want some general thoughts on what it is and what might have been done to it, posting some photos on here will probably get you some opinions. Then, depending on where you live your best bet would be to bring it along to one of the shows where collectors and other knowledgeable folks set up, and show it around to a few of them. Again, not for a formal "appraisal" but some input on where/ when it was made, etc. Some of the shows have different areas of focus, but if you go to a big one like the CLA or even Friendship you will find some people who will help. For a formal appraisal, you would need to go to a reputable, knowledgable dealer and probably pay for the service. Again, some folks on here could point you in that direction if that is what you would like to do.
Good luck
Guy