Hi, I'm an an admin on FICS. Most interfaces set the "interface" FICS variable with their name and version. That is useful to FICS staff when giving users help or enforcing our rules.
At present Scid does not set an interface string when connecting, but the included simple patch makes it do so. Here is the string shown on my system with the patch:
Interface: "Scid/4.5.2 (x11; Linux x86_64; rv:Nov 2013) Tcl/Tk 8.5.14"