If you haven’t read the Pre-1985 FRT5 article, I suggest you do so before continuing on in order to understand some lingo I mention here (but it’s not totally necessary).
Something important to note is that the “FRT-5” name to label the whale tail style Floyds eventually gets named the “FRT” at some point with using 100, 200, and 300 names after it (e.g. FRT-100) to identify the color.
From here on out, the FRT-5 Schaller-Germany Floyd Rose, often called the “original” Floyd Rose (and eventually labeled simply the “FRT” in catalogs), went through varying but virtually unnoticeable changes from 1985-2020. That being said, when given a closer look, there are ways to identify them. Sustain blocks are a good way of identifying FRT5 time frames.
If anyone knows the exact dates of these FRT-5 variations discussed, please contact me.