You keep saying " featherweight " BUT, are they 221's, 222's or 301's? 221's with a blue circle on the badge will be a centennial and be worth about $50.00 more than one that has a regular badge no matter what shape it's in. 222's on the other hand are well worth about $75.00 to $100.00 more. 301's are slant needle and it depends on your preference.
Serial numbers would do a world of good in these cases.