If you go to viewtopic.php?f=19&t=2982&p=5875&hilit=Reed+%26+Barton+Catalog#p5875, you will find a page from the 1885 Reed & Barton catalog of bells that were silver and gold plate. Your bell is the 15th picture down the page. It is identified as No. 070, Pear Shape, $5.50 per dozen. Most likely, it was silver plated, not gold plated. So, I think it would be safe to assume your bell is older than 125 years.