I knew you were being sarcastic!
The companies we rebuild stuff for tell us to use what ever we think we should use. The material call outs are shit we don't have, like 1075. Sometimes they call for 1045, when the carbon number can vary +/-4, so 1040 would be considered nearly the same thing if you account for its carbon number variance.
And, if you ever get the chance to have some metric sized TGP (turned/ground/polished) material quoted....do it.
We had a customer yell at us, in our shop, because he said the price was too high.
We told him "This isn't Europe. Places here do'nt stock metric TGP. Its special order"
He told us (in his own words) "There aint a damn bit of difference between metric and american." :baseball_wassat:
According to our material supplier, the difference was about $1000.00 for a 12 foot piece between the 2.