Hello, welcome to the Colt Forum!
I'm no expert but I had kept personal notes on the Colt model LE6920 Colt's Law Enforcement Carbine/ M4 Carbine since the beginning 1998 up to the current production which was 2019, but they won't be no longer available to the civilian market this year.
Yours according to my notes is made in around 2005, the last serial number in my note from 2005 was number LE0255XX and the earliest that same year was LE18XXX.
Here are the usual features and markings of that year 2005:
Markings on top of barrel between the flash hider and front sight base: C MP 5.56 NATO 1/7
Marking under the handguard on top of barrel behind the front handguard cap and below the gas tube: date two digit month (01 - 12), slash (/) and 05 year (you have to remove the top handguard)
Upper right rear marking of detachable carry handle: Forge symbol markings Cardinal (bird head symbol), Cerro (keyhole & number 10 symbol), Anchor Harvey (splintered horizontal letter A), etc.
Front of upper receiver above the gas tube hole have M4 or 4 marking.
Upper receiver picatinny rail have letter T and numbers.
Upper receiver behind the shell deflector, right rear: Letter C and forge symbol codes keyhole, splintered A, stylized letter D (Diemaco), etc.
Lower receiver left side mag well: Colt's Law Enforcement Carbine CAL. 5.56MM
Lower receiver left side above selector-safety lever: Colt Defense
Lower receiver right side mag well: LE restricted markings
Hammer and trigger pins: large type 0.170" diameter (newer since mid 2009 are small mil-spec size 0.154" pins)
Bolt carrier left side below the gas key: letter C
Bolt carrier group type: M16 full auto, (the lower rear most of carrier not machined off)
The mil-spec buffer tube have four positions.
Handguards are the M4 military type fat, oval section with double metal heat shields inside.
Buttstock mostly military M4 type with waffle type feature.
Let me know what other markings or any difference of your carbine.
I only have two newer model LE6920 M4 carbines, a 2011 marked Sporter M4 Carbine and a 2012 marked M4 Carbine