Hi, I am looking to buy on ebay a Seiko 5Y30-5060 watch manufactured in the 1980`s. This is fitted with a standard round gold plated crown. There are several other similar models from the same decade that have cabachon crowns fitted as standard. I would like to swap the crown for a cabachon one but do not know whether they are intechangeable. I would appreciatew opinions please. thanks jack.