Iver Johnson imported them about two years or so... by then, Lou Imperato had acquired the old factory where he
began an arrangement producing 2nd gen BP series Colts.
You probably know of the Colt , Uberti , Val Forgett , Lou Imperato/Iver Johnson arrangement.
You'd also find Iver Johnson marked Griswold & Gunnison & 1860 Army's at the time.
Imperado when on to found Henry Repeating Arms, he passed on about 6-7 years ago.
Iver Johnson imported Remington's Mint , un-turned in the original box may bring a bit of premium,
because of their rather short run.
Unlike the BP series Colts made here, the Iver Johnson guns were imported and will have proof marks etc.