the basic story is Keosayian was well connected at Colt and into machine guns. Had access to anything he wanted. Supposedly lent them millions to avert bankrupcy at some point and had big clout there.
Used legit registered SNs. If the gun no longer existed (destroyed, demo'd, damaged, lost, whatever), he'd remake a new one.
If he wanted the latest roll marks, even if they didn't exist in 1986, e.g., NeoGeo's "M4 Commando Enhanced", he destroyed an old receiver, reused the old SN on a new receiver with different roll marks.
They made mistakes. After the 1989 restructuring, "they" (i.e., him and his nightime [or were they broad daylight?] helpers) put the COLTS MFG CO INC rollmarks on the gun, proving it was manufactured after 1986. I almost bought one with those rollmarks and "M4 CARBINE" from Spiwak when the collection started moving in about 2016. Figured it out and shied away, because before all this came to light, there was a pall of paranoia about these guns, and most of the so-called gurus said stay far away, they're contraband and so on.
When A2 receiver forgings were exhausted in the early 00's, they started using A4s, leaving another telltale sign of a post-1986 manufacture. Other telltale signs are Colt black anodizing; unstaked castle nuts (I have a 9mm DOE like this from a PA dealer Targetmaster); no dabs of paint on the bolt release roll pin hole; no armorer marks on the right front of the upper receiver; and a "NIB" gun in a Colt box with no labels, put in a plastic bag with the blue lettering, but with a post-1986 date on the bag, manuals in the box with post-1986 dates, front sight post forgings with post-1986 dates, the list goes on. He assembled "NIB" guns with whatever was on hand, and obviously by 2006 or so, earlier printings and forgings were scarce. One dude tells of going into his house to buy a gun and him sitting there and giggling, taking a "new" box from a stack and putting the gun and accessories in there for they buyer. It's said he had many hundreds of Colts, as well as a stunning collection of other MGs.
FOIA requests show two manufacture dates for these "remake" guns. BATFE used to allow this in 1990s and early 00's; folks were sending in Olympic lowers regularly to have them "repaired" basically meaning new receiver. After some time, BATFE put the Kibosh on this.
He had ties to PA dealers like CCA and TM. Spiwak got some guns too. Felon Vaughn Kelerchian of autoweapons was his nephew. THat explans a lot too. Some have called it the "Armenian MG Mafia" (Keosayian and Kelerchian are Armenian names.)
Apparently he got some kind of rapidly progressive dementia diagnosed about 10 years ago, and the collection - which was LEGION - began being disbursed/liquidated to the dealers, mostly in PA as far as I can tell, but they have shown up EVERYWHERE.
I have 4 Colt MGs. I'm pretty much sure they're all Keosayian guns even though all but 1 I think were not remakes. Auto marked A2 is too black and upper is 1999 front sight post forging, and I have a FOIA; I have an A2 carbine that's all original, but from PA dealer, so suspected to be one of his, though not a remake; I have a POUSG A2 -and I'm pretty sure these are all pre-86 guns. Finally 9mm DOE, SN ~HT00015xy that may be a remake, or at least an after-hours assembly, because the castle nut is not staked. These are the horses I have in this race, so to speak, and why I'm so interested in this topic.
