This is a 431G, with chain-stitch & freearm. Just the ‘Top of the Line’ Slant then, & still very impressive now, 50+ years later.
This is my best Slant machine & just perfect in every way. I know its history & feel priviliged to be its current custodian. You will see the odd examples on ebay occasionally, but usually they have problems, (some not obvious) missing parts/attachments, or grossly unreal prices. Buyers beware, but the more you know, the better you are to judge: )
I’ve got 3 of these currently & the worst one still performs excellently, despite its mainly cosmetic problems… It’s my ‘goto’ machine for everyday use.