Yes
It should have the caliber marked on the barrel,such as"38 Colt New Police".
Only Colt would know.
Depends on which police positive with sn 134551: Colt police positive special -1916 Colt police positive .32-1916 Colt police positive .38-1921
1919
no
Try here http://proofhouse.com/colt/
Don't know the value,but a Colt police positive .32 with that serial # was produced in 1908. Or, 1909
value depends on overall condition. if your colt is a police positive special, made about 1921
Colt police positive .38 was made in 1919 and Colt police positive special was made in 1914.
about 1907
1921
if a police positive special made about 1913