The older exposed ejector rod Colt Detective Specials were NOT rated for +P ammo.
Especially not the pre-War versions, which were made long before the +P was invented.
With the 1972 shrouded barrel Colt DS, Colt did rate them for +P ammo.
The early 1970's guns were rated for "up to" 3000 rounds of +P, after which the gun was supposed to be sent in to Colt for a check up and "possible frame replacement".
In the later 1990's, Colt revised the rating to "Factory inspection every 2000 to 3000 rounds", with no upper limit.
The aluminum framed Colt's like the Cobra and Agent were early rated for 1500 rounds, later revised to factory inspection every 1000 rounds.
Since there are no new frames to be used as replacements, and +P will accelerate wear, it's a good idea to do most of your practicing with standard .38 Special ammo, and use the +P for "business".
So, as long as you have a post-1972 Colt, with the heavy shrouded barrel, the use of +P ammo is OK, taking into account increased wear on the gun.