Again, shipping dates based on serial numbers are only a guesstimate. I based it on guns from my collection. It certainly appears that your C 60051 gun should have shipped between February and August of 1949.
C 2077 11/1948
C 46336 1/1949
C 53207 2/1949
C 84786 8/1949
Also, not knowing the exact date of the month can throw these numerical calculations off as it could be the first day of the month or the last day of the month or any day in between. As shown with my January and February guns, they could have shipped 58 days apart or 1 day apart.
From the above it appears that production was very heavy between November of 1948 and January of 1949. Then it appears to have slowed down to around 5,000 guns per month.
These are just guesses based on the limited data available and as stated earlier, the only surefire way to know the exact shipping date is by historical letter.
Since this is a family gun, the $75 fee may be well worth the investment. Some folks find it fascinating to see where a gun shipped and where it ended up.