That Hamburger Marys used to be a famous family hardware store called Bumby's that was built in the 1890's and closed in 1966. I haven't got a clue if it was used for the occasional pop-up event. It opened in 2008.
A plaque was added between 2015-2016. I have an image of it, but i'm having a hard time with resizing the picture to make it fit the storage limit, so heres a link.
https://imgur.com/a/dfCUN
Also, the gate mechanism that your talking about with the counterweights is a RACO gate mechanism, it's probably from the 60's or 70's. I'm probably thinking the crossing was installed in the 60's or early 70's by the Seaboard Coast Line.
I'm not a crossing upgrade geek. But i'm predicting the changes.
The WRRS 12x20 inch lights on the bottom were replaced with Harmon Electric 12x24 lights in the 1980s.
The WRRS? mechanical bells were replaced with General Signals Type 1 E-Bells in the late 1990's or early 2000's. These bells are at a low pitch which i like the pitch of it, high pitched GS type 1's sound terrible.
When SunRail was about to be in service, two tiny pedestrian signals were placed in the middle of the tracks with GS Type 2's. The GS Type 2 bells ring continuously, while the GS type 1's ring until the gates lower.
One of the RACO gate mechanism's were replaced by a Safetran gate mechanism at an unknown date.
The WRRS gate lights were replaced by RECO at an unknown date, then replaced again by NEG LED gate lights.