What serial number range did Colt start using small .154 pins?

I’m buying a new Colt AR 6520, curious at about what ser. number range the switch to small pins took place in the Govt. Carbine. I of course have to do an out of state transfer so I want to confirm the likelyhood of small pins with the seller.

I know this has been asked here before, but for some reaon I cannot get the search page to load.

Thanks!

https://www.m4carbine.net/showthread.php?t=74125

Tell the seller to simply Mic’ the holes…it’s much easier than waiting for a definitive answer on colt pin sizes on the internet imho.

If you know what serial # it is call Colt. I did about a 6920 and they said they get called about it all the time. One rep played stupid but another looked it up in about 3 minutes.