the real mystery is the size. I don't believe either the 605 1/2 or the 5 1/2 were made as a pre-lateral. Very interesting!
I thought the same thing at first, but if its a 5 1/2 size, they didn't get manufactured until 1889, which put them well into the type 6 territory.My guess would be an early Stanley Bailey bed (type 4 or earlier) and a bunch of repairs/replacement parts.
Also could be one of the companies who began making Stanley clones after the patents expired.
Is the inside of the depth adjusting nut stamped "L Baileys Patent" with 2 dates? That would indicate its from a Stanley between type 2 and type 7. Otherwise you've got either an off brand or a really mix-and-match frankenplane.
Like I said just a guess.