#3A Folding Pocket Kodaks -- that's the 3 1/2 x 5 1/2 size -- are like oysters. Some contain pearls, others don't. Finding a pearl can require looking in many oysters.
#3A FPKs were fitted with lenses whose focal lengths ranged from 6.75 - 7.25 inches. The good ones (Special and Autographic Special) had, among others, f/6.3 Tessar IIb lenses in Compound or Optimo shutters. These are very good lenses even by today's standards and cover 4x5 with ample movements. Some of the cameras had f/6.3 Cooke Kodak anastigmats, i.e., good triplets, also in Compound or Optimo.
To learn more than you thought you wanted to know about FPKs for the US and Canadian markets, see http://mgroleau.com/catalogues_kodak/ . The site in in French, the catalogs are in English.
FPKs made for the UK market had a wider range of lenses from all of the leading makers, can be found -- sometimes -- on ebay.co.uk and even turn up in the US.
p.s., study the catalogs to learn to recognize the crappy lenses. If an FPK has a Ball Bearing Shutter, it has a crappy lens. Bottom-of-the-line and all that.