Some early Navy-marked guns were pre-Victory (no V prefix). I'm not sure when the V was separated from the number. I'd assume grips are replacements, but whether they are factory or not, I can't say. Closest Navy-marked SN on my list to your V87950 is V89795 which shipped on 9/2/42. But S&W was making around 1,000 per day at that time, so yours would likely have shipped around the same date.