Hi Mike, welcome to myBulova. You are most fortunate to have this wonderful watch as a memento of your grandfather. I think family heirloom watches are fabulous things. The 18K gold case puts this watch at the top of the line, no question this was an expensive watch in the day. The 17P movement dates it to the mid 1920's does this correspond to you grandfather age, or could HE have inherited it? Without a date code on the movement I would suggest a date of 1925. Look through the advents we have from the 1920's I didn't see an exact match but several are very close. My guess would be that it's a model 470-something, but I can't find anything specific. have it serviced if you intend to use it, be very careful not to over wind it, be gentle with it.
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