Good question.

By the designation on the tool itself, it looks fairly early.

I have a lot of weird and wonderful stuff in my toybox, but I don't actually have a genuine SMLE "multi-tool"; all I can go from is the data in the original manuals and use my new headspace gauges along with digital calipers or micrometers etc. as suitable. Bear in mind that ALL metrology equipment for "serious" use is supposed to be re-certified at regular intervals; gauges, despite being fairly tough, can actually wear. Rust is an absolute killer.

Maybe I should start a new collecting line!