That is what the tappets always look like when the cam goes flat. *shrugs*
I have a hunch that modern engine oil is to blame for your flat cam.
In Austin Healey land, we've discovered cam destruction is often related to today's oils vs yesteryear's flat tappet technology. A brand new cam, with propper assembly lube and break-in, can go flat in < 1,000 miles on a healey! The big healys sport a big ol' cast iron I-6 tractor engine very similar to the FJ40's engine.
Today's oils often have less of some critical additives. (Zinc Dialkyl DithioPhosphate in particular (ZDDP))
Here is a great link: