@gwoptics they're made to last around 30 years, sometimes far longer. This one does seem recent though as it appears to be cast iron as opposed to wrought like all the old hardware was. You can still get it but wrought iron is generally reserved for high use doors as it's more expensive. I can bet it's Sargent because that tubular style is their default and the other companies that copied it have a shitty casting and finish that doesn't look so good after 10 years. Then the older companies that made that hardware all got "acquired" and shelved to not compete with the new brands. Even Sargent is acquired by Assa Abloy, an acquisitions company, but somehow Sargent's factory has remained a last bastion in holding out against corporate interests. I wouldn't even be able to guess how that's possible, but there it is.

The history you never needed or wanted.

edit: If you really want to know if it's new or old, look at the side of the door. it the part that sticks out (the bigger one, not the little one) has a black pastic contact where it would strike the door jamb, or white plastic. Black plastic is old, white plastic is new.