There's really no way to give it an exact date just the era they were used.
As info the ACL ceased to exist in 1967 when they became the Seaboard Coast Line but they had used the name Atlantic Coast Line starting in 1871 but being that it's an Armspear lantern it'd be after 1902 as that's when the company changed its name from Railroad Signal and Lamp company.
They were produced up to the 1960's but were manufactured by the Adam's Westlake company.

Here's a site that can give you some more info on them.

http://www.railroadiana.org/lanterns/pgLanterns_Armspear.php

Now it's Super Bowl Time!
Go Broncos!!!!

Always looking for Frontier and Beeline items.