The Colt you have is the gun that replaced the Junior.
The Junior was made by Astra,and the GCA 1968 banned it from importation,so Colt started making them here.
(My how things have changed at Colt's over the years,some of the more recent managment would have rolled over and just not bothered with it).
Anyway,the serial number should have a prefix of OD,and was made in 1970,
the first year of manufacture.
Serials started at OD 01001,and ran through OD 10001 that year.
My book shows OD 120,471 as the last gun made in 1973,and the gun was dropped in 1974,and as far as I know,that was the last 25 ACP gun Colt made.
Hope this helps,Robert.