Descriptions and part numbers of the Singer slant needle buttonholers:
301/301a: This is in a burgundy "coffin" box that is plastic (like the old green singer buttonholer boxes). It should include 5 metal cams, a plate for the machine and two screws, one to attach the plate to the deck of the machine and one to attach the buttonholer to the presser shank. The buttonholer is black like the old machines. The part number 160743.
The one I have for the 400, 500 and 600 machines is in a cardboard box as shown above. It should include the buttonholer, which is metal, 10 plastic cams, the cover plate for the feed dogs and one screw to attach it to the presser shank. It has a partial photo of a 600 series machine on it. It just says, for "Slant needle machines" with no disclaimers. It has a label pasted on it that says. part no. 102577, the number under the label is 161829. I found a buttonholer on Etsy that uses the 161829 number that appears to be identical, so it appears that both are good parts numbers for this buttonholer. However, my buttonholer itself does not have a part number actually engraved on it. The plate is part number 161825, which is the same plate the 161829 part number contains. The copyright date on the manual is 1967.
The final one I have was an add on when I purchased my Touch and Sew, model 778. The buttonholer , itself has a hard plastic case , and is marked "Gt. Britain" on the bottom, but it has no part number on it. It has 10 plastic cams, the attaching plate (which has no part number on it) and the screw that attaches it to the presser shank. There is no part number on the buttonholer, itself, but is stamped GT. BRITAIN. The box has two numbers "SIMS 4642" and 381116 for the buttonholer. It says on the box that the "plate 383013 furnished is for the use on 700, 900 and 2000 series machines...For 401, 500, 600, 620 and 640 machines use part 161825" (which is the part number on the plate in the 400, etc. box.) The manual's copyright is 1973.
I do not have the "pink Jetson"one, which is a slant machine buttonholer, so I don't know what it fits.
bkay