Colt Police positive special was made in 1913, police positive .38 was made in 1915 & police positive .32 was made in 1910. I believe the butts were square until about 1932 when they were rounded.The small r, I believe ,would be the inspector's mark.
if a police positive special made about 1913
about 1914
It will be located on the butt of the frame. You may have to take the grips off to see it.
made about 1930 made about 1930
Made around 1917.
1924 was the first year for wood grips. 1924
for grips try: edssportshop.com
Go online and type in "colt revoler grips". You should find everything from factory replacements, to custom grips made to fit your own hand. Prices from 2-3 dollars on ebay, to over $100 for custom grips.
The Police Positive came with black plastic rubber until 1927, then went to wood.
Possible. Only way to know is to get it lettered by Colt
200-600 or so 6in barrel police grips serial # 60099
dated about 1906...value depends of condition i.e, metal finish, grips, rust or pitts, bore, etc. go to: Gunsamerica.Com and look up Colt pistols for values