I’ve got the Gaggia Factory too - it’s post-mil. I’m really happy with my Coffee-sensor naked portafilter. It’s not perfect but it’s very, very nice.
Edit: just don’t go for the ‘official’ one with the rounded lip at the bottom. Stock basket is too deep and drips catch on it, flying everywhere. IMS basket won’t even fit.
Yeah, that’s what I’ve got. Doesn’t fully rotate into the grouphead if the handle’s fully threaded in (although that’s a couple minutes with a file I haven’t bothered with yet) but otherwise real happy. Proper solid bit of kit, weighty. Just feels nice.
So this one would be your recommendation?