While browsing in an antique shop today I came across some Singer buttonholers. Both are complete sets, including manuals. One has the Singer Brand on it, it's manual has a 1948 copyright, and it is priced at $7.50. The second one is in a Singer case, has a manual distributed by Singer, a 1956 copyright, but the brand name on the buttonholer & manual is Griest. It's price is $15.00.
What I'm wondering is if either one of these will work for my Featherweight and/or 15-91? If yes, which one would you get?