Beautiful 18sz WALTHAM 21 Jewel VANGUARD, First Run!!!! I have #60273669 and have only seen a few of these over the years and all were 17j marked only adjusted with a different plate pattern. Do the experts know if there was an upgrade at the end of this first run or if this watch was held back and finished later, returned and upgraded or maybe was a custumer special request or even someody at the factory upgraded it for themselves? Any input welcome.