NOS No1 forend identification?

[Surpmil]

That forend looks like it was made on a pantograph judging by the irregularities in the inletting. Very much doubt it would have got past inspectors looking like that. Certainly doesn't look like anything that was produced at RSAF Enfield IMHO.
Still, it has some convincing looking dust inside, could a stack of "seconds" have been sitting around this long? Possible, but doubtful and if it was a second, even more doubtful it would bear the Enfield stamp - something easily made in an Asian workshop these days.