It's not always easy to find hard numbers on replacement forks, but IME modern affordable replacement steel forks are not particularly lighter/lightish in weight. I think it's both for production cost reduction and for a mfr liability cushion in the face of gov't safety regs. I just checked some of the loose forks around here, all steel blades/steerer:
No-name replacement; Origin-8?: 1090g (long threadless steerer)
Nirve Fairfax production fork: 1010g
Soma/Tange replacement: 920g (long threadless steerer)
'90s Bianchi Eros production fork: 880g (for 61cm frame; threaded steerer)
'79 Fuji America production fork: 820g (for 61cm frame; threaded steerer)
'00s Zanconato custom fork: 800g (beefy big-boy build; frame's name was "Stomp")
'80s No-name Columbus SLX road fork: 770g (for 61cm frame; threaded steerer)
'82 Proteus 531 custom: 710g (for 61cm frame; threaded steerer)
I suppose "lighter/lightish" is always a relative thing, as in compared to what?, but I'd think you'd have to be getting close to 800g in steel to qualify as lightish. You're going to find those as used higher-end vintage forks, not off the rack from Surly/Soma/etc.
My Soma fork looks fine---built well, nice finish, inspires confidence. But I wouldn't call it lightish.
Paul Brodek
Hillsdale, NJ USA