Thanks AR. Knew Colt had 20-rders during Nam, but did not know the history on the 30's. Mine have the light green followers, and the bottom floorplate, reading left to right starts with the: Colt rampart CAL. 5.56MM
Colt's Mfg. CO. INC.
Hartford, Conn.
U.S.A.
Your Colt mags are the recent production which started around the early 1990s up to the start of the assault weapons ban 1994, then after the ban they added the month and year date outside the mag bodies, they all have the same light green followers (very early ones had the old black non anti tilt followers, they all have the same floorplate markings of (Pony) Colt CAL. 5.56MM Colt's Mfg. Co. Inc. Hartford, Conn. U.S.A..
Before 1990 back up to the early 1970s the floorplates were marked:
"(Pony) CAL. 5.56MM
Colt's Firearms Division
Colt Industries
Hartford, Conn. U.S.A."
The number 33710 on the mag body are the Cage code of Okay Industries.
Additional reply:
Sadly I only have one Colt 30 rd magazine with the older non anti tilt black follower, no date markings and the Colt's Mfg. Co. floor plate, pre ban from the late 1980s.
I used to have about a dozen same pre ban mags after the ban ended but I mostly gave them away to friends and relatives when they're having mag problems.
Most of my 30 rd mags now are teflon finished D&H Industries/ Tactical brand (over 70 mags) they bought out LaBelle which used to be a US military supplier, the mags are as reliable as Colt and other USGI suppliers but the teflon finish are tougher, more slippery and last longer.
I also use other polymer brands like Magpul PMAG and Lancer Systems translucent, I actually prefer to use my polymer mags because they're stronger and trouble free so far.
If you would like other brands that Okay Industries are making same as Colt but at lower prices take a look at NHMTG, now is another time to get more mags while the prices are lower.