Yes there is a way but it does cost a little money. What you do is take it into a Reputable repair facility and talk to the most experienced technician that you can find there. Do this 2-3 times. You will not get a definitive year but you will get a 5-10 year range. They look at the workmanship, finish and other areas that are present on the horn. They will then give you their best “guess”. I have found that they are usually in the ball park. They usually also agree on the same period of time. 5-10 years in the life of a horn is not that big of deal.